We just had one per wheel. Committing 10 motors (4 drive, 4 steer, 2 tank) to the drive train is a lot to begin with. We would have been ALL drive train if we went for 2 775s per wheel.
We lost a few (<5 between practice and competition robots according to my memory). We theorize it had more to do with the impact from the defenses than stalling. The brush holders were breaking rather than melting/disintegrating. Just a theory, though.
And thanks for the kind words. We sure like our swerves here in Mountain Home.