Back in 1936, Allegheny Ludlum Steel and Ford Motor Company collaborated on the production of six stainless-steel-bodied 1936 Ford sedans. Pretty cool idea, but that wasn't the end of the stainless steel Fords!
In 1960, Allegheny-Ludlum and Ford built a pair of stainless steel Thunderbirds. Perhaps best of all, they made three stainless steel 1967 Lincoln Continental convertibles. These are solid stainless steel cars, not the steel-laminated plastic of the De Lorean DMC-12, and all but two of the '36s survive to this day. Check out the Allegheny-Ludlum site on the cars and the Michigan Lincoln & Continental Club site for the whole story. Thanks to VintageRacer and 57Sweptside for the tip!