The two sets I'd love to have on the Cartel Market would probably be:
The Mercenary elite prototype, or at least a variation of it, not to bothered about the color:
and the High Sorcerer Adept robes:
They are both in the early 30's level wise, much like the gear that is already on the cartel market so balance-wise I guess it could work, and you also don't get people moaning about how cool somebody looks at a lower level than them either!
Also, just because the worst that can be said by you is no, I'd love to see Revan's robes and mask too!