I have a Zero Image 6x4.5/6x6/6x9 pinhole camera with a 'focal length' around the one being discussed (40mm). With a good pinhole the fall off on monochrome negative is negligable. It is very wide - something like a 20mm on 35mm format - aperture around f/235. I have some results here: http://www.btinternet.com/~g.a.patte.../ptpinole.html
Film was Delta 400.
Using 120 film means that film advance is done using a red window to look at the frame marks on the backing sheet. If you make a camera capable of 6x9, you can set internal masks to work smaller.
Zero Image is at http://www.zeroimage.com/