The anniversary boards are quite simple. As Nicholai has said, I have made quite a few of them–some as simple as black foam-core board for short term trials of barrel lenses I had access to but didn't own or want to more permanently mount.
The 4" square, 1/4" thick, is flat and needs only to have its bottom edge beveled on the inside so that the board can be tilted into its slot on the standard. Another layer of material can be added to the back, with at least a 1/4" set-back from all sides to act as a further light trap, but I haven't found it necessary. My most commonly used material for boards is Masonite, or hardboard. MDF (medium density fiberboard) seems to be taking over in most situations around here (eastern US) for many applications and I have also made boards with that. I usually just draw two lines from corner to corner on the front to mark the center and drill out the lens opening. For up to 1 3/4" I use an old-fashioned hand drill using an auger bit. A hole drill is used for the larger openings needed for old brass projection lenses, etc. I make the blanks 4 or 5 at a time and drill the holes as needed. If you are careful in your measurements, the threads of a lens or shutter without a flange can be screwed right into the masonite, cutting its own way in as it goes. Wax helps. I haven't had any problems, but you should be careful to make sure they are firmly attached to the board before you go jogging around with the camera and have the lens fall off!
I sold the Anniversary Speed to Nicholai and now have to figure out new strategies. The Pacemaker boards are much more difficult to jury-rig.