Norm Abrams (sp?) (New Yankee Workshop) did a show on this issue a while
back. He found a shop with flip down caster benches and built one that
way in that show. I tried to look at the links another poster gave for
flip down casters, but it didn't work.

Here's the link you need to Norm's mobile bench:

http://www.newyankee.com/getproduct.php?0207

Pete Stanaitis