Here’s a thread from a few years ago that shows how to put a VBrake onto a Magura mount without a commercial adapter.
When I made that thread the gallery on this forum worked, but it was taken down along with all of the photo’s. If you go to the last page you’ll find the photo’s that were originally included in the first post.
It was really easy to mount. And it worked really well. Thanks for bringing this up. I may try it on my MUni, I’m not a big fan of the Maggies, and since I’m not running a 3" tire I don’t need the clearance. After all, the clearance of large tires was the reason Maggies were adopted on unicycles in the first place.