I recently was taught how to do the cross-eye 3D technique and I suddenly want to take medium format stereo pictures. A cursory googling shows me there is a Russian purpose built camera to do this, and a few ancient plate film cameras from Voigtlander and F+H. For any of you folks in the know, are any of these good options? Or is home-brew a good idea (i.e. strap two TLRs together)?
The Sputnik is a pretty good performer -- i have one and enjoy using it. You should flock the interior to cut down on internal reflections, and it takes some fiddling to match the f-stops of the two lenses which, because of the way they're mounted and linked, can get out of synch.
Another option is two slr cameras with the same lens -- two rolleicords, for example, both with 3.5 tessars. I mounted them on a single bar and bought a double cable release which was easy to synch between the two cameras. Kind of a heavy rig, but good.
Finally, there's the original Rollei stereo camera, the Rolleidoscope, which uses 120 film natively and is a handly little shooter, very nicely made. The slightly earlier Heidoscope uses or plates or an alternate roll film back, which is amazing if you can find one, it uses 120 and works wonderfully.