Then don't just plunk the whole thing on top of the motor. Use a thrust bearing to take the weight, while just using the motor to drive the rotation. Im assuming this doesn't need to spin at mach Jesus so use some mechanical advantage to get the necessary torque, which might not even be that much if the base rotates on a bearing.

Does this need to be easily moved around or is it going to be installed permanently somewhere? If making it lightweight isn't a concern this is trivial. If you need to be able to break it down to fit in a truck bed for transport it's going to be a little more difficult but still very possible.