Lance,
Here's another source of metal for you. I buy a lot of metal from these guys in small lots from their Richmond location. They have a store in Phoenix if I remember right. As for the surface, my table is bare steel since it would be pointless to try and paint it. If it gets a little rusty I just run a sanding disk over it and that takes care of the rust. In Phoenix I can't imagine you will have much of a rust problem due to humidity.
https://www.metalsupermarkets.com/