You could contact Hugo Zhang and have him get you a price to have Chamonix build you a back and 3 holders. That only solves one problem though. Maybe you could get the folks in China to make some rolls of 12" wide film. A couple of rolls 12 inch X 150 feet. Any soluton is likely to make the cost of the original camera pale in comparison, but still, 12X15 would be very cool.