"large, tame, easily bred" = burmese python, lol. since it appears you are looking more toward lizards, let me throw out a few things. for the most part, the larger lizards need much more room than snakes, esp if you are considering breeding. a good rule of thumb is that the minimum length of the cage should be 2x the length of the lizard, the width should at least = the length of the lizard. with arboreal species, you can sacrifice some of the ground area in favor of height. obviously, this leads to a serious space commitment. (you can use smaller housing for some lizards, but if you are thinking about breeding...). then there is feeding - monitors eat A LOT. I'm not trying to talk you out of them, but to do it right is a huge commitment - space, time, and money (depending on your sources).
As for other suggestions - first identify what size range you are looking for (guessing
2 1/2 - 3 1/2 ft, based on the species mentioned), what do you consider "tame" and what are your plans regarding handling (are you going to be doing alot of it, or just for routine care), are you willing to deal with full spectrum lighting (many lizard species require it), what temperature range will you be able to accommodate, do you have a preference regarding food (meat vs plant)?