Funny I should find this topic in print now. Last week I built one out of scrap I had laying around. I got tired of 'someday' and tired of working on the floor. Had the legs already welded into a topless frame (auction find) that I cut down a bit in one side, and a piece of 1/8" plate laying next to a barn (mostly flat). And a new plasma cutter to help clean it up.
It ended up ~2 1/2' by 3'. I left it in a slightly 'L' shape so that there is an exposed place to leave a corner/joint exposed for welding. I am going to have to remember the angle iron welded on one side. Good idea. I haven't added a bar for hanging clamps on (yet), nor a hook for grinders. Haven't used it enough to figure out the 'right ' place.
It's small enough that I put fixed casters on the outside of the back legs and pieces of 3/4" emt for handles (slide into the sq tube frame). The other legs have a plate welded ot the bottom with a large bolt for a level adjustment. Not bad for a quick project -- but nothing nice like yours. I'm off of the floor though!