The maximum speed would be 1.09 RPM or so. By pancake motor you mean the 28BYJ-48 5v stepper motor?
I have seen some people using it for this project. Some say it is strong enough and some other say that it is not strong enough for a camera with a big telephoto lens. That why I think the Nema 17 17HS4023 might be a better option for me.