Most rotisserie motors are 1 rpm I belive. You can by them online,I just can't remember where. I built one a couple of years ago with a 1100 rpm motor and just geared it down. Little sprocket,big sprocket,little spocket,bigger sprocket. But the proper rpm motor is best to begin with. Check out sybbq.com. They might have what you need.
I like those too!
I'm not sure what type your talking about, if it is the shelves rotating or just a spit like a hog roaster.
But for a hog roaster, they have a pretty good motor on Amazon;