[EricH]

Come to think of it...

I'm not sure you want a motor, per se.

Figure out how much torque you'll need to move what you're moving, then go down to your local hobby store that deals with large R/C stuff. You're looking for a good-sized servo. (Servo motors are technically motors, but they're set up to hold a given position rather than run at a given speed--unless you're making a continuous-rotation servo run at speed.)

The bonus here is that servos are rigged for linkages (say, a pivot) so you can really open up your options if you work it right. They don't rotate very fast, necessarily. And, they're relatively cheap. You'll just need a controller--the RoboRIO has servo slots, as I recall, and I know that Arduinos can handle 'em.