Another approach I've taken to making a camera permitting multiple exposures onto paper is the so-called "Carousel Camera". See this link on F295.
Here's the front view of the camera. It's a two-story camera, with two carousel sections, one above the other. Each story holds four 4x5 negatives. There's an operating knob on the top lid, which is used to rotate the carousel into each of its four positions, permitting a total of eight exposures:
Here's a front view, showing both shutters open. In practice, only one shutter at a time would be used:
The view of the carousel, looking down inside the camera, top lid removed. The two holes are engaged by bolts from the rotating knob, to rotate the carousel:
The two bolts in the lid that are turned by the outer knob. Note the light trap mechanism:
The carousel removed from the camera. Note the curved film planes; you could design a carousel camera for flat film, but the width of the carousel would be bigger. It's made from sheet galvanized steel (inexpensive, easily found in hardware stores) that easily solders together, then roughened up with a wire brush on a drill, then sprayed with metal primer and flat black:
There's a short protrusion on the bottom of the carousel, in the middle, that engages a nut that's been glued to the bottom floor of the camera, acting as a crude bushing permitting the carousel to easily rotate.