I've gotten rare mounts from every way possible. I ninja'd the white hawkstrider from a group in H MgT by Master Looting right before the boss died. I've paid for the mounts from 10m 3d, ZA and 10m Uld Hmodes. I've also farmed ZG, strat and H UP many times to get those. The point is you have to do anything and everything possible to get the rare mounts. Never give up, never surrender...and if that doesn't work...lie, cheat and steal.