I remember watching videos of when the Desert gene first came out. Big breeders wanted to put the Desert gene into a whole bunch of combos because it was so awesome. Turns out that they had problems with fertility of the females, apparently they have problems getting egg bound or laying all slugs. A few people still work with the morph but not many, in fact if you look for Desert combos on Morphmarket as of right now there are only 11 for sale. I think it would be a neat project to get into, especially since it's not very popular. You could do some really neat stuff with combining it with some of the more recent morphs like a Scaleless Desert or Desert Pied, not sure anyone is even thinking about those combos and for sure they would be the worlds first. Maybe you could even find the trick to getting females to produce.
Caramel Albino is also a neat gene to work with, but apparently it has kinking issues. I've seen all kinds of snakes kinked up, and some breeders with Caramel Albino don't have any issues. Could be a certain line of the morph that has issues. I actually have a few females that are het for Caramel Albino, thinking of working it into some neat stuff like a Caramel Pied or Caramel Scaleless Pied, I bet no one is going after that one either.
I think some morphs with issues would be a neat side project to work on, you could really fine tune the issues and perhaps find a work around to bring those morphs back into popularity.