I've got a few ideas. First off, it seems this has been posted elsewhere, and as of right now I have only read this thread, so sorry if I'm missing something.
I just went back and checked all of your breedings and I think this works. You have been talking about the morph "buff." Lets say there is a dominant (as you've been saying) gene called "buff." now, it can't be on the amel locus because, if this were true, a buff het amel could not exist, and so your first pairing that originated these animals wouldn't be possible. So we have the Buff locus now. My first big question was, what are oranges genetically? is a buff and amel in one animal. Now I hope this hasn't bee answered, and I missed it, but I think I have an answer, and hopefully the answer. I believe an orange is an amel het/homo buff (that is amel buff). I won't go through all the breedings, but every single pairing you have done makes sense when this is true and buff is dominant.
the only pairing that messed me up for a moment was your orange X orange pairing. In this case one of your oranges was homo buff, as well as amel. That will result in all hatchlings being homo amel and at least het buff, which means they are expressing both traits. All of them would be oranges, just what you got.
So I think you do have a new gene! Congrats! I would like to see someone do some work with the amel genes in both emorys and corns, and caramel, but I'm pretty convinced your right about your snakes. Please not whit emory becaus then it is mixt up and not pure enymore. Speaking of which, I wonder how hard it would be for me to grab a pair from you when I'm in Europe this coming summer...