I like those guys, I was fortunate enough to see Jeff Holloway's collection (http://hollowayherps.com/) and he has animal that would make you drool.
Now as far as mutation I know NOTHING, Jeff would be a good guy for you to talk to when it comes to those guys he has be working with them for 20+ years
Thanks for the link. I just visited his website and WOW those are some really nice animals