[auganov]

AFAIK gynandromorphism doesn't happen in mammals because sexual development is more centralized. Half of your body could have cells of a different sex but it wouldn't matter because organs responsible for sexual development will still effectively turn out one way. In other species each side of the body will develop quite differently because different cells is all it takes.

Tons of different human mosaics have been observed but it usually doesn't cause anything interesting.

Having different hair would imply chimerism - having two different sets of DNA. With mosaicism you start from one set of DNA but it may not duplicate the usual way.