I'm on board with this, though I'd recommend designing the film chamber to accommodate intact (i.e. with bridge) Minolta and Kiev cassettes (the latter distinguished by a smaller diameter takeup core that would hold 30 frames instead of 20, and an advance cam that compensated diameter for the longer roll, at least with thin base stock). Much easier to load and unload if you can get a nail under the bridge, rather than having to fight to get the empty supply chamber out of the camera. I'd also recommend the Kiev 13x17 or Minolta QT 13x18 frame (both of which were offset on the film, for compatibility with 16 mm single perf movie film loaded with the perfs on the bridge side). In addition to Kodak and Ilford, you should surely bring Fuji on board, too (to give a choice in color films), and be sure to support chromes (including correct opening slide mounts) and see if you can find a work-alike for Agfa Copex Rapid, the best microfilm stock I've seen for scenes and portraits (needs a low-contrast developer, but does a much better job at higher film speed than other microfilms -- virtually grainless even from 16 mm, at EI 80).
I've owned and used 16 mm cameras since I bought my first Minolta 16 II and Minolta 16 MG back in 1981 (when I could still buy preloaded film at most drug stores and any camera store). I've long wished for a hybrid of an Edixa/Rollei 16 (very adjustable, manual camera, but with a cassette-rewind system like a Kodak/Leica 35 mm, only shrunk) and a Minolta (for the quick/easy cartridge load and reloadable cartridge).
