Over half of our animals are green tree pythons and when we showed up to our first expo of the year this year with 25 hatchlings that we produced we stuck out like a sore thumb. As far as I know we are the only people at any of the shows we vended at this year that had GTPs. I don't think they're the next BP by any means partially because there is only one true morph available and it's so new that nobody is selling (even hets were over $10k last I saw). Their husbandry is not hard, but it's harder than for a lot of beginner snakes, and these guys sometimes have an aggressive streak that balls don't have.
One other thing is what's involved in incubating eggs. They are VERY intolerant of mistakes made by the breeder, where if a drop of water gets on them over the course of 7 weeks they almost always rot unless immediate action is taken. Personally, I hope they don't really take off because there are a lot of people out there that like them just because of their appearance...I think we'd get a ton of people without the proper knowledge and experience trying to keep them and I think a lot of them would fail miserably at the snake's expense.