From my time on the E-feds I've got three ideas I could use.
1) An anarchist who only wants to cause chaos, regardless of whose side he's on. He would be a great tweener, he could just switch sides at any moment, as his only purose would be to upset the established order, whether that's going after champions, or taking on the management.
2) An Adrenaline junkie who always looks for the next rush of Adrenaline. (I'd be like Jeff Hardy mixed with Sabu)
3) An ex-pro surfer who came to pro-wrestling after a big injury (Tyler Rek's first gimmick, but I'll make it work)