There are some sellers on ebay, too. I just bought a fish from pdxspirit on ebay. I don't know about form, but I received a very young, very healthy fish that was bred here. He's beautiful and the communication with them was fantastic. They seemed genuinely concerned about the fish's welfare.
This is an interesting question, though that I've often wondered about myself. . . what do breeders do with their fish? They surely can't keep them all, yet, there are not a whole lot of American breeders selling on the internet. If anyone out there knows, I'd be interested in finding out.