I converted my garage to a workshop as well. I made a bench at the head of the garage from a full sized solid core door and then ripped another door in half lengthwise and lined the wall with another. The main work surface is in the middle of the room. I bought these legs and casters from Rockler:

http://www.rockler.com/product.cfm?page=10276

and attached a full sized (80x36) solid core door to it. I can roll this into any area I want. When I paint, I kick my wife out of her side and roll the table into her free space and hang plastic from the ceiling to create a makeshift paint booth.

-Ben