I thought I would share this for those that might be interested. It's from Japan and the description translation is difficult to understand, but it looks like it comes with two 75mm lenses and one 127mm lens? Nothing looks like it's linked in terms of focus, apertures, or shutters. You can see two individual shutter release cables in a couple of the photos.

Downsides are 3 stereo pairs per one roll of 120, everything will ALWAYS be hyper-stereo, plus there's no way to enjoy the full impact of a stereo pair where each side is 120 mm wide with the viewers that we currently have.

https://www.ebay.com/itm/Private-Made-6x12-Formats-Stereo-Camera-w-75mm-Lenses/283299692903?hash=item41f5fa4167:g:vy4AAOSwmaJb7X13:rk:23:pf:0