yeah, sort of
I used two hinges bolted together and hung a wooden (teak ply) mounting platform on the port side companionway frame. it swings out of the way and hooks to the inside cain wall (as you are thinking) when not in use. I still need to come up with a good idea to hold it in the companionway position with some kind of a 'breakaway' design, and easily moved for access to the cabin when sailing. I will try to post a photo. I tried to use a store bought bracket, but you really need a double pivot to make it work