I shoot mostly large format, so I have 4x5, 5x7 and 8x10 cameras and film holders. I've built 5x7 and 8x10 pinhole cameras (the 5x7 survives, the 8x10 wasn't built well enough to last for more than a couple of months of use,) but 10x16 isn't a standard film size, so there are no film holders I could buy for it. I could go to 7x17, which is a standard size for which cameras, film holders and film are available, but alas, ultra large format film holders are expensive and so is film. If I'm going to go larger than 8x10 I need to keep the cost as low as possible, thus the paper negative path with half-sheets of standard sized photo paper.
Putting paper on a roll-film sort of widget I had thought of and discounted; perhaps I should re-think it. Maybe I'll sacrifice a sheet of 16x20 paper and see how tightly I can roll it without creasing the paper. That'd be rather fun to use, I would think!