Need help deciding what to power the E-Revo with!

[Dafni]

Can't help you with the HV gearing.
Coolhand is right, my favourite motor in the Revo is by far the 7XL. Nice mix of runtime and speed, and tons of torque.
You can run it on 12 to 18 cells. I mostly run 14, and geared to an optimistic 35-40mph I can run pack after pack without thermo-worries.
I once ran 16 cells and geared it for a theoretical 50mph, and the motor was well in the save range after a full pack on a parking lot.

Edit: I found the 9L was nice and smooth, but the 7XL is even smoother. I can crawl around easily, with gobs of torque.