We wanted someplace to stash our laptops for charging without cords all over the rig, so I modified the design of some magazine holders and hung them against the rear wall of our 21. The transformers fit between two laptops and the cords plug into the curb side outlet a few inches away. The rear paneled wall leans back 20 degrees below the ETI screw covers.
I have a footrest/table brace between our benches, so I attached the holders to that. Would be simple to have the back side an inch taller and re-use the ETI mounting screws, but I was too lazy to take things apart.