how about something like the old polaroid 500 portrait camera
3 levers/buttons you push down. each one is a shutter that exposes at 1/60 o r80 o r40 or whatever
the film doesn't need to move at all, u have 3 different cheap plastic meniscus lenses and a little box around
each of the films / lenses like an egg carton.
you push 3 times that's it
send it in to be processed, remove the flm fold it in half and send it back to you
to have the shutter rods pulled out, shutters cocked and 3 more flms installed.
have fuN ( fun project ! )
john