Not sure if this is what you are considering or not but thought I would share just in case.
This is the corner platform that I built to hold my FF and to hold my Navionics App device. I also have two 12v sockets mounted underneath and well as my switch box that controls power to the various parts of the boat and a time/air/water temp display. The right side stereo speaker is mounted there as well.
I built it using some scrap aluminum that I had laying around and it has been very useful.