To keep it "simple" I would consider an 8x10 pinhole that uses 8x10 holders but no GG. Perhaps using one of those peek-a-p-boo thingies you put in your front door to see who is there as a viewer.
I would have an adapter built to be able to replace the pinhole with a "real" lens and shutter (perhaps a 210mm lens -- carefully measuring the distance to take advantage of the hyperfocal distance). See the Hobo Camera as an example. That way you have the best of both worlds.
The camera would be about 8" thick (less if the 210 lens is on a cone to push it farther from the film plane). Another lens possibility would be a Wollensak 159mm (6 1/4") lens which are great lenses -- especially if no movements are needed, and would keep the camera thinner. There are also more expensive Schneider 165mm lenses, too (Super or regular Angalons?).
PS...could not find a photo of the actual "Hobo Camera", but here is someone else's designs