I understand this is an older thread but just came across it.
So, as far as genetic variation, this is what Ive heard/read..
That very few dumerils were imported over from Madagascar, something like 6 or 8 then no others were able to be imported over due to restrictions..is that correct? If so, then, yes, genetic mutations could pop up, but, it is so unlikely.
On the other hand, they are popping up, mostly overseas. I would not go as far as calling this snake a new morph. It looks like a nice looking dum to me. I would not buy it as a morph. But, if you do your research, there are T+ albinos out there, i.e. what many would call ultramel or caramel or something along those lines, and there have also been hypos produced. Pics can be found in the kingsnake forums if I remember correctly.
I have 2 dumerils which are extremely dark, one with a pure black belly, so, obviously something went weird with the genetics on that one.
Okay, sorry about the rambling. I just would not purchase it as morph unless it has been proved to be genetic rather then a mutation due to something else.
Thats all folks.