Gray bands are a very enjoyable and rewarding species to get into. I don't know that I can answer all your questions, but I'll tell you what I do know. Of course, as far as morphs go with gray bands, there are alterna phase and blairs phase as your basic "morphs". However, over the years there has been several line bred animals that have given off other things like hypo and such. This type of thing I'm not all that familiar with.
Regarding price? Well, there's a lot to that. There for a while the prices really dropped, but are now seeing a pretty good rebound. For starters, some people have a fairly high mortality prior to hatch. Myself and others have experienced full term babies completely dead inside the eggs. Then, once you have healthy little babies, it can be a pain getting them started on pinks. The loss and effort involved in producing alterna are probably partly to blame for higher prices. I had to go out and collect lizards for my baby alterna today. That time and effort translates to me not wanting to let go of them for a lower price. Unfortunately, even in this market, sometimes the effort to get these animals on pinks is not equivalent to the price you get for them. Some people, myself included, are willing to sell snakes not on pinks yet. I am very sure to disclose this to any prospective buyer and a lower price reflects this fact. I also make it clear that after I put a bunch of lizards into them and effort in getting them switched over to pinks, the price is going up.