I designed a mount and another fellow made them. He still has some left. As for price, I believe the last few have been anodized red and also blue. The mounts are $29.00 + shipping. These mounts have a single hole which is slotted to adjust CG. The mounts are milled to accept a 4-40 Nyloc. I can provide pictures if interested.
I posted these some time ago on here, but they were not readily available. They were a "Buy It Now" item on Ebay. Here are the pics from the post when the mounts were mill finish.