The first thing you have to consider with your plan is why these species are not worked with. There is a reason ball pythons, crested geckos, leopard geckos, bearded dragons etc are bred in such huge numbers. Lots of people want them.
I don't know what the demand is for rear fanged snakes but I would have to guess it is rather limited. You may have success getting rid of the offspring from a pair or trio of a few different species but I don't think it would be enough to offset the costs (IMO)
Another thing you have to look at is the WC availability of the animals you are considering. If cheap WC animals are available that will cut into your sales potential as not everyone is willing to pay a premium for CBB animals. I only bring this up in reference to your especially those that one cannot easily find as CBB's comment. I can't speak to the WC availability of the ground boas, Indo tree boas and rear fangs you mentioned.
I'm not saying it cant be done and in some ways you may have an advantage over all the morph breeders. The morphs that make the most money when sold obviously cost the most for you to obtain as breeding stock. If the animals you want to work with are less expensive you can get started with less money. Of course the downside to this is your babies will sell for less money. Another advantage might be that if no one is working with them you won't have as much competition when trying to sell them. Of course you won't have as many people clamoring for your animals either.
You sound a lot like me. I'm not so much into the common stuff but a lot of the uncommon stuff is uncommon for a reason. Its not because people don't like them, its because enough people don't like them to make their commercial propagation a viable venture. Working with inexpensive animals that are widely available as WC will not make you any money as long as the WC are available. Finding a rarer species, like some of the Australian geckos, since you mentioned you like terrestrial geckos, will cost a bit more but they still seem to sell well, the problem is they don't produce a lot and they are becoming more common and the price is dropping.
As far as feeders, unless you are huge you won't make a ton of money at it if you consider the time and effort you put into it. Quality food is not cheap for a large colony. Bedding is not cheap if you plan on having a colony that won't have your neighbors calling the cops on you for odor control. Meaning of course that you have to clean often. Just these two things alone will take a decent chunk out of your profits and that does not even include your labor.
When I had my 20 mouse colonies and 50 or so breeder rat setup I used to like to think about how increasing my stock could make me even more money. I'd figure out how long it took me to clean each rack system and project that into how many systems I could clean in a day and in a week on a decent rotation. I'm young (stop laughing those of you who know me) and I still need a day job so I figured my job might as well be raising rats and mice. Then I figured out how much food and bedding I went through with my two racks and extrapolated that. Then I calculated how many babies I could produce and how many I could, theoretically, sell. Then I figured out how much work I would have to put into it. Not only the daily work but the weekend shows for selling and stuff like that and I figured out if I just walked the sides of the roads for 8 hours a day and collected aluminum cans I'd not only be better off financially I'd probably be healthier (except for all the exhaust fumes I'd be breathing in.) On top of that I see how much the rat and mouse market has dropped recently and it make the future look all that much more bleak. A lot of people go to the pet store and pay 1.50-2.00 per mouse and 5.00-6.00 per rat and think wow, If I raised a couple of hundred mice and a couple of hundred rats a week I'd be doing OK. The problem is you probably won't be selling yours for that price. I was selling most of my stock at retail, live and frozen, in my own store but even with my low production I was usually running a surplus so I would not be getting retail prices for any extras I produced. At shows, around here anyway, you would be lucky to get 75 cents per adult mouse and maybe 3 bucks for a large rat and most of your sales wouldn't be large rats.
After all my negativity as strange as it sounds I still wouldn't mind giving it go. If I could start out without putting myself deeply into debt and I thought there was decent chance of making a profit I would try it. Believe it or not cleaning rodent cages didn't bother me and I know there would be things I could do to make it easier (automatic watering system for example, I used bottles and they needed to be refilled every 36 hours minimum) It's just a huge commitment of time if you want to make a decent amount of money. It's not an 8 hour a day 5 day a week job.
If I had 300 to spend on breeding stock (future breeding stock) I know what I would get in a heartbeat. Viper geckos. They are easy to keep and breed and they breed at a young age so acquiring young stock wouldn't mean I was 2 or 3 years away from production. They wouldn't take up a lot of space. They were once fairly common so everyone knows about them but no one breeds them in huge numbers anymore. Babies still seem to sell well at a relatively high price. Lastly and most importantly, I love them. I would have them even if they didn't breed for me and that is very important to me. I don't want something that I only have because it makes me money.
If I had a little more money, say $1000.00 I'd go with Rankin's dragons for the exact same reasons as the viper geckos. It doesn't have to take a lot of extra money to get something going.
You have taken the first and possibly most important step. You are asking questions beforehand. There is nothing wrong with starting slow. You don't have to have a dozen breeding colonies from the get go. As others have suggested, choose a species you want to work with. I'd highly suggest something that means more than just a potential for profit to you. Spend what you can afford on good stock. This may even mean WC stock depending on the species but make sure you get it healthy (vets etc.) I would also suggest something that has a least a bit of a following as a lot of the really obscure stuff might be a tough sell simply because no one knows it exists. You want something that the demand will at least be equal to the supply (preferably higher but at least equal to.) It doesn't matter if you have 10 of the rarest baby snakes in the world if no one wants them you won't make money on them
A well thought out project or two and even a small business, if successfully implemented can make you some money, but my last piece of advice, if you are thinking about this as a way to make a living, you may want to reconsider. I am certainly not saying you can't as many people do but most of them are not doing it like you are planning on doing it. They are much larger scale. Unless you have a colony of Centralian blue tongue skinks (my ultimate goal) that you inherited from a dead uncle (not part of the goal as none of my uncles have them) you probably are not going to make decent money from a small scale project.
Notice I didn't even say "If you are thinking you will get rich" because I think most people have realized this is just not going to happen.
I don't want to discourage you though so after you have thought it all out and have decided to go for it I wish you the best of luck.
They are all commonly worked with due to their morphs, and also that they appear to be very prolific, which is personally amazing for any species to go through as that not only cuts down on the risk of populations in the wild dwindling.
Perhaps it's different now a days, but there was a huge market back in the day for rear fanged snakes, and there still is from what I have read, though the information I've read recently might be out dated... I am also aware that if I had the money to branch into ball pythons, it would not be something that I would be happy doing, and with some of the money the morphs could bring in I might be stupid for not going that route, but I honestly care less about the money at this point, as much as I care about working with species that I enjoy working with, the added bonus to picking snakes that I enjoy working with, may not even allow me to break even, but it'll do two things in my opinion 1.) bring these species into the spotlight, and educate them to their existence, and 2.) lower the costs of the upkeep (I know, best case scenario.)
I can find diadem rat snakes for sale on websites, however I am not sure the credibility of these websites, or if they are a scam I have looked on Kingsnake, as well as Faunaclassifieds, they cannot be found from a trusted source or at the very least, not from me.
I do know that as we speak LLLReptile does have some Indo tree boas in stock, that I am contemplating on picking up, due to the price range I assume that they might be LTC, but the species might just be inexpensive.
My intentions are there that if they cannot be sold, then I will keep them all until I find suitable homes for them, if that does not happen then I will keep them indefinitely,as they are still living beings and despite being primitive I feel they deserve to thrive a happy, and healthy life, though with that being said I would not be afraid to cull in worse case scenarios.
There are a lot of lovely species of Austalian Geckos, do not get me wrong and while I could get into breeding them, what good would that actually do for the species? I might be mistaken about a few of the species I want on my list to work with, but I want them due to the fact that 1.) Not many people actually work with them, and two those that can be found more often then not appear to be WC, now I am not going to go off on a rampage about how WC is 100% pure evil, I feel like WC species can be an amazing thing especially bringing in fresh blood.
I do not want to make money off of feeders, sure I may sell my surplus however I want to know what I am feeding my own reptiles, is safe and healthy, with that being said I figure three colonies of mice, three colonies of rats, three colonies of African Soft Furred rats., and perhaps some roaches for a snake for the rodents as well, as the lizards.
Is that twenty mice in total, or actually twenty colonies and what were you keeping that the time, that you had needed so many feeders?
I am against it due to the fact that vannila extract is made from alcohol, and while it is more than likely 100% safe, wouldn't this cut down on the ammonia now when you say your own shop, do you actually run a reptile shop, or at least have any pull in, or are you just an employee probably bad wording, so please do not take offense but if you know many vendors, perhaps you might be able to help me out man?
A consideration, I am sure that you have already looked into, but have you taking into account the feeders that you are feeding off for your stock, and then the reptiles in the store? then selling off the surplus? and it is still a money sink?
Maybe this is not a small scale reptile breeding business that I want to set up, at the moment as my intent is to work with what I love, to hopefully get some of the more over looked snakes to become more popular, and if I can even break even, or close to it, then I am content,
Rankins are really cool dragons, I love the fact that they are a smaller version of a bearded dragon, take up less room but are they still pet rocks, or do they have any personality to them?
Another totally random species that I would love to eventually work with would be Chinese Cave Gecko's they look absolutely stunning and from my understanding you can set up a pretty good looking naturalistic vivarium for them,
I could honestly care less about selling at the moment, and maybe even in the beginning I will use surplus rats, and rodents and any off spring to barter with, be it cages, or other reptiles, I am not in it for the money as stated, I will more than likely bring the over looked snakes to the table vs. the while beautiful ball pythons I may eventually get a breeding pair or two of Boa Constrictors, or a few other more common reptiles to bring in the crowed but beisdes that...
Mind if I shoot you a PM?
