What kind of RPM are you looking at/need for the motor?
The Gear/axle ratio and desired output rpm will be a deciding factor.
Are you committed to 120vac?
DC motors such as Golf cart style and a Automotive battery is one option.
For a start, you could place a torque wrench on the input shaft to discover what the break-away torque is required by the motor, this is assuming you already have the unit and drive train in place to experiment on?