The store didn't have any extension tables or rollers on hand, and I didn't feel like going through the trouble of ordering one and waiting for it arrive; So I just bought some aluminum and went to work. No plans, no written measurements, just a rough mental image and a few basic tools.
If anyone builds this I'd love to see your version!
Step 1: Supplies
For tools you'll need: a ruler/tape measure, a ratchet, a wrench, a drill and/or drill press, some drill bits, a hole saw, a hacksaw, a file, and a micrometer/caliper is handy.