I personally think it's going to be FOREVER before they are able to get GFP into a reptile - consider you have to get the genome altered, get it in an egg, and then get that egg to hatch - so like - surgery. And depending on how much development goes on inside the parent snake, you might have to start the process before the egg is even laid.
(the first thing i wanted to do with GFP when i learned about it was put it in ball pythons. It seems a pretty tall order)