Albino checkereds aren't too tough to find, although I don't think there's any around right now.
San Frans, you're right, it's all about finding them from a source that you can be comfortable that they haven't been in-bred, and if you want a pair to potential breed from that means finding them from two breeders. There's a few breeders in the UK, and several more in Holland. Ironically, it may be easier to find a San Francisco during the breeding season than it is to find many other species.