Try here, for a start

Here is a link that might be useful: MasterMetalWorks

You could try Room & Board, but prices can get up there (although if you live where they have a warehouse/outlet--Minneapolis, I've heard the sales there are fantastic).

You might find it more cost-efficient, tho, to look at similar tables as a whole-- base and top-- at sources like CB2 and West Elm. My experience has been that the tops screw on, so whatever top you're planning, you'd probably be able to conceal any unnecessary hardware.

You've been scoping out your local craigslist, right? Even a really bad-finish piece could be worked on by you or a place that does powdercoating (I took my black steel Crate & Barrel TV/media stand to a place that normally does stuff like custom motorcycle painting, and for $100 it gave it an aluminum finish--better for my decor for less money than it'd cost to buy something else.