In my arsenal of junk labeled "future projects" I have a geodetic camera transport which was made for 9 1/2 inch aerial roll film. It rolls the film across a 9X9 platen like an aerial camera. Please contact me off line and buy this thing from me. It is sophisticated, electrical, has canon plugs, probably cost somebody a million dollars, is heavy, and would intimidate a guy who could run multiple Cirkut cameras at the same time. Still, since you started this post, I thought perhaps you'd be a perfect candidate! 7 contiguous pieces of 35mm film can span the 9.5 inches. You'd roll them up side by side on the supply reel and they would play across the platen to the take up reel. It doesn't incorporate vacuum so the pressure from supply to take up is what would hold them flat I suppose.
jimgalli at lnett dot com
L N E T T
ps, I have no idea if it works.