Backs for these view cameras show up occasionally on ebay. I purchased a 4x5 back for my 8x10 this way. It came from a different 8x10 camera. I knew the chances of finding a 4x5 back for my poor camera was an absolute zero. So, I asked the sellers specific questions about the dimensions of the backs they were selling. Eventually I found one that appeared to be very close size-wise. When I received it, it didn't quite fit. I had to use a router on the corners, and now it works great. IMHO it's better to alter the accessory to fit your camera, and not to alter the camera too much.