I think Bob Salomon posted about the Linhof motorized 5" rollfilm back somewhere and mentioned that very few were made, and they've ended up in libraries or museums that do high quality copy work in volume.
I've seen a back for 5" rollfilm for my 5x7" Press Graflex. I forget what the numeric format designation was. I considered purchasing it, but I decided that sheet film is easier, and I've got two bag mags and a couple of Graflex holders for that camera, so it wasn't worth it to figure out how to respool 5" rollfilm with an opaque numbered paper backing like 120, so it could be used with the back.
I think that that's the real obstacle (in addition to film flatness) to using rollfilm in this way. You've got to design a back with a feeler wheel to meter the film distance traveled, so you know how far to advance the film. It's a little more complicated than those Chinese rollfilm backs with the red window.
I guess one model might be the film advance mechanism in the Voigtlander Superb TLR, which has a feeler wheel geared to a frame counter, but it doesn't have auto stop, so you have to watch the frame counter, just like the red window, to make sure you don't miss the next frame.