I was wrong...there is at least one very recent patent application claiming the establishment of transgenic snakes expressing GFP!........including ball pythons, king snakes, and corn snakes
See United States Patent 20080005807
Some of it very technical (which isnt too big of a problem for me) but its also very legalese ......But it is worth a read....It is pretty interesting......
I recommend reading "Egg Injection and Incubation", "Hatching and Propogation", and "Utility"
Bob Clark seems to have provided the animals......