I really think you'd be a whole lot better off building the frame from scratch. I used 8020 exclusions because I have some available from a project I decided not to currently pursue and they allowed me to easily make adjustments as I was trying out various options and configurations. The frame and most of the rest of the parts can be made with hand tools although a standard drill press would be useful. You could also buy extrusions from:
http://openbuildspartstore.com/They are little smaller but should work fine and are cheaper than 8020 extrusions. A rigid box-like frame out of MDF were also work.
The tabletop was a 6 inch wide piece of flat stock steel (not plate) purchased by the inch (cut to size) from Speedy Metals.
Craig