Agree, it needs to be a relatively high torque, low RPM motor, unless you want the ghost being spastic. Mostly, they are done with wiper motors or similar because they provide both the torque and the low speeds necessary for a nice effect.
Rotisserie motors are very similar to wiper motors in torque and speed. Most run at 4-5RPM. A variable speed Dremel runs at 5000-35000RPM.With all due respect to the J-Man, I say go for it. I'm not very mechanically inclined, but with instructions from the internet( youtube videos and a willingness to innovate when needed, I did fine and you will as well..
BTW, I used a barbecue rotisserie motor and it works great. very slow motion, no undue drag on the motor.