FYI:

Found (and ordered) a Ronin Universal Mount Adapter for 66 $ at Famoushobby:

http://www.famoushobby.com/mv124 ... -for-1pc-p-619.html

Much cheaper than Cinemilled / Roninrigs....

Should arrive today. Will report....

Already arrived. Works fine.

It's built for the classic (Big) Ronin, but it fits also to the Ronin-M. The only downside is, that with the Ronin M, the Security Pin locks only on one side, so you have to take care a little bit more to tighten the screw on the adapter.