I guess an anodized aluminum dark slide wouldn't be cost friendly. Of course you could offer them as an upgrade. I look at a filmholder as a long term investment. So I wouldn't mind paying a little more for my tools. I mean if I'm going to pay 5000.00 -7000.00 for an ULF camera then 500- 600 for a film holder wouldn't be out of the question. It would be worth it if you are on a shoot and you have to fuss with a warped darkslide and miss the shot, or if it is not seated properly end up with fogged film. Some people don't realize that the film holder is actually more difficult to make than the camera. At least they have to be closer tolerence work that is.