To anyone who is interested, this has worked for me. A 12v automotive wiper motor makes an inexpensive and easily available motor/reduction unit for paddle drive. Most are two speed, but the DC motors will work with variable voltage speed controllers as well...(the torque and rpm's are in the right general range). The ones for the rear windows and hatches are generally single speed and smaller in size. Mounted upside down with the motor below and the gearbox up, a low COG can be maintained. Hope this is helpful.
James