I'm gonna throw an idea in from left field. How about two druids?

Watch MrLonghair's Moonkin PVP videos. They basically consist of two prowling cat-form druids sneaking up on some poor sod and popping into caster form for some Moonfire spammage. It looks like a blast! So if I were you, I'd level up two balance druids and then respec them as one feral tanking spec and one resto spec.