I looked into this too, with RFF member Roger who lives in Japan. We were a bit disappointed to learn it's not simply an adapter that allows various G lenses to fit an M body, but rather a permanent re-locating the glass lens elements into a new lens barrel. So the cost is applied to each lens modified, and there's no going back. I think this operation no longer makes much sense, given the easy economical availability of the Zeiss ZM series lenses.