If you were to use casters that lock, such as a
foot lock device, you will probably be able to keep the
base stationary. The best example I can give is the little casters that are often used on file cabinets. They often have a little lever that you kick with your
foot to keep the casters from starting to
roll. The only pproblem is that I do not know if these type of casters are available in large enough sizes. I would guess that they would be available but I am not familiar with all of the types of casters available. The other issue would be whether or not the locking device would be anle to withstand both the weight of the set piece and the torque that will be created each time the doors are spun. It looks like you have a very good idea based on your drawing. On the outside of the door, you will want to use non-locking casters. They should also be able to swivel. As long as all of the casters are well lubricated, your idea should work.