There's probably quite a few people here on AC that have them, a lot of my originals came from here.
Anyway, I don't think any crayfish are hermaphrodites. Marmorkrebs/Marbled crayfish are all females, they don't have male organs present, too. They reproduce parthenogenetically. Though, not the only crayfish to do so, they are the only ones that have one gender, all other species (that are known) have males and females.