A couple of years ago we were looking for one that was like a thick piece of wood with large casters. We never found it and were actually toying with the idea of making one... but got sidetracked and never did. We're not sure if that's what you had in mind, but if so, check out our Top 10: Funky Casters.
This post on Unplggd mentions several TV Stands (including the
no-longer-available Min Media Stand from DWR) -- some of them could be set on casters.
Other ideas, anyone?
Note: Include a picture and your question gets posted first