The Kodak Stereo Camera was made from 1954-59, and takes 24mm square exposures on standard 35mm film. Its body is made of brown bakelite, and it has a handy bubble level which you can see when you look through the viewfinder. I got lucky with this one -- it had a "buy it now" of $15 !
Zeiss Ikoflex This beautiful camera, presented in 1934 and almost instantly nicknamed 'coffeecan', had a special mission: to beat the Rolleiflex , world's first TLR. In fact, it never doubled Rollei's success.