I knew physics class would come in handy someday. 
I was looking at stall torque to choose that motor, the other ones on that site seemed to weak to get the arms up. I don't seem to see that specification on most of the other motors I looked at.
So it seems like I want something that can vary from 10-60rpm. Should I assume that a motor capable of 60rpm can vary that much? does the speed change depending on the voltage? I'm thinking something like http://www.allelectronics.com/make-a-store/item/DCM-518/PRECISION-GEARHEAD-MOTOR-USED/1.html or http://www.allelectronics.com/make-a-store/item/DCM-365/6VDC-GEAR-MOTOR/1.html would be good to start? Would those be small enough to work with the motor shield?
Thanks for the help.