This is crazy but I'd like to design a small camera to take 16mm un-perfed film. With a frame size of 12X16 and a layout like a Rollei 35 but only 1 inch thick. Two front facing dials, one on each side of the lens with shutter speed on the right and aperture on the left. A fixed 25mm f2.8 Tessar design with front element focusing to 1 meter. There would be available a +1 and +2 close up lenses. A 22.5mm filter thread. A folding viewfinder on the left end that is interchangeable with a reflex right angle finder. The plastic cartridge would be exactly like the Minolta 16 cartridge but without the bridge (I have several Minolta 16 cameras and when the bridge broke on one of my cartridges I removed it entirely and the feed/take-up pair worked fine without the bridge.) A two blade leaf shutter with 'B' and 1/8-1/250 and X-sync at all speeds. With a standard 1/4-20 tripod mount thread and shutter button that takes a standard cable release.
Since I believe (for myself) that film photography should be DIY then I'd wish for Ilford and Kodak to offer 100 ft. bulk non-perfed 35mm film in several B&W types. Then with a slitter one could get two 16mm strips on 35mm with only a 3mm waste strip. Oh, almost forgot, would like Paterson to make 16mm reels for their tanks.