I encountered a Graflex 1234 holder for 4x5 film and have loved using it to hold crazy things to put behind a lens. Was there ever something similar made in 5x7 or 8x10? Basically, some sort of film holder that can be gutted (or come hollow like the Graflex 1234) and then you can stuff anything you want in it? The only sort of similar thing I know of are the single-sheet Polaroid holders, which are too thin inside to be useful.