I am looking to drive a disk at relatively low speeds (9rpm) and somewhat high torque (not sure on exact numbers, 100+ in-lb.) I am looking for a motor that can plug directly into the wall and just spin at 9rpm. Where could I find something like this?
If you are willing to accept that one would have to attach a cord and a plug to match the outlet, one can use a microwave oven turntable motor. I have disassembled a number of discarded microwave ovens and found a few that run on US mains power (110vac) and a few that don't. The ones that don't get very very hot and run very very fast, if one does not pay attention to the labels attached.
My microwave oven turntable rotates at 6 rpm and is geared down by a substantial amount which would provide quite a bit of torque. One can consider that such torque is necessary to spin food products which can be massive.
If 6 rpm is too slow, a 1 to 1.5 gear ratio increase could be implemented. The shaft of these motors have a D-shape profile, making additions reasonably easily implemented.