When seeing the DIY tilt-shift lens described here a few weeks ago, Ted, one of our most active commenters, mentioned that he had done about the same for a DIY high-quality slide duplicator.
Here is how he described his craft to me:
As I did not want to put my hard-earned money in a new one, I bought a full frame slide duplicator on eBay for 5€. Since my camera is an APS, the lens was too far from the rear mount, the slide mount was too close to the lens. Moving the lens closer to the rear mount was easy (just had to reverse-mount the lens internally, check the diagram below), but the slide mount was still too close to the lens and out of focus. So I torn the slide mount apart, and added a small PVC pipe to lengthen the distance between the lens and the mount. As the PVC pipe diameter did not exactly match the original design and was a bit loose, I secured it with a metal clamp. This allowed some added flexibility to perfectly adjust the focus.
Since then I digitized more than 4000 old slides from the 60s, and I’m perfectly happy with it.