I recently had the need for a lens mount, and instead of trying to find one I just made one (well, several, actually). They're 6061 aluminum, the hole is sized for 4-40. The cutaways are sized to allow 20mm and 22mm lenses to nest in them. The center of the lens will sit at .645" (same height as an Aixiz can in a mount).
Anybody else interested in these? $6 a piece plus shipping.