I really like the prot pally + 4x shadow priest idea. I'm currently running 4x shaman instead and am quite happy so far (level 55) but 4x VE/VT, auto facing thanks to mind flay, and 4x renews (out of form) really excite me. I don't have the experience to back it up but I've got to think that with 4x renew + PoM + 4x VE would mean you almost never had to cast a direct heal. I think even a Shadow priests renew will do 400/tick at 70 (so 1600 in this scenario) + w/e VE returns and bounce that PoM around by casting Shadow Word: Pain. Yeah to keep renew and PoM going you have to stay out of shadow form but if you had to drop and direct heal you'd be out of form anyway. Maybe on pulls you set renews and PoM then shift to nuke the first mob asap but now Blizz made the switch out automatic so that part is easy.

Gonna have to try this at some point.