Check out wheeled plant stands at HomeDepot, I think they may be suitable for your use. I use one under my tube amp.
Wheels under tube amps?
Can tube pre and amps be put on wooden boards or glass shelves with wheels without any loss in sound quality? Or must the rack be heavy and stable? I am looking for a practically solution for my equipment that at the moment are placed directly on the wooden floor underneath a big sideboard. Can't have it on top, they are too big.