I have read an article in a magazine promoting a metal spray machine that will fix rusted through hard to find body panels and such. By the pictures that I have it looke like a big mig welder where the gun is fed two wires that come together at the gun end and arc. In the middle is high air pressure (1000 or more psi) that blows the molten metal at the surface to fill large and pin holes, also builds the metal up to be ground back to smooth. Here is a link that shows some results with an article for those who are interested

http://www.jellybeanhotrods.com/metalspray.htm

just an option to some who are looking for that hard to find piece that maybe now can be saved instead of replaced.