[joshvm]

On film availability. It's relatively easy to slit film to width, with little jigs that are machined or 3D printed. This is popular for Minox "spy" cameras since new 8x11 reels are $20+ and you can refill an old plastic cartridge if you're very careful. The stock is about 8-9mm wide depending on the camera and so a 35mm roll will yield 2 strips that can be cut to length.

Some enterprising person makes a machined an aluminium Minox film cartridge, which is expensive, but solves the problem of the originals being incredibly fragile. It doesn't take many retail rolls to justify the cost though.

https://juliantanase.com/about-minox-film-cassettes-old-and-...

Here's a 110 slitter: insert https://www.camerhack.it/product/110-film-cutter/