I agree it makes more sense it isn't a hybrid. Balls definitely aren't native to Taiwan or Thailand(don't remember which), so that means someone would have had to breed for it. You don't accidentally breed for a pied burmball. Also I find it hard to believe that if he bought it from someone, and dust produce him it self, that they would sell it as anything other than what it actually was. Also there is a snowball's chance in hell that it is a wild caught pied burmball. My guess is it is a pied burm, that he a) hasn't breed b) hasn't had any success with breeding or c) hasn't been able to prove out.
Does anyone know if it's male or female? Could be a big reason why we don't have any.
I guess it's also possible that all of the offspring, if he tried to breed it, that all of the viable offspring were of the same sex as the piedburm.