[BrianG]

A Feigao S motor is roughly comparable, but are a little longer and the coils fill up the can more, so there is a little more torque/power for a given kv. Don't know if the "35k rpm rule" applies to the smaller Feigaos, but that's something to think about. However, since the S has more torque, you can gear up a bit to compensate.

Otherwise, maybe a 1509/1D might be a good choice. But for the price, you could just pick up another 7700 motor...