Brian, I just finished running HT wires in my walls yesterday, and ran into a similar situation. I bought the same banana plug wall connectors that you did (four banana plug receptacles/plate). For future upgrades, I wanted to allow for some expansion, so I bought three of them. Like you, I didn't want to cut a bunch of holes in the wall for them, so I bought a "triple gang" box from Home Depot and a triple wall plate to fit over the three banana plug plates (I believe it's called a triple GFI wall plate). There are several versions of gang boxes available - some are designed to be nailed to a wall stud, and there's another type that's designed for retro-fitting, so to speak, and clamps to the drywall as the screws at the corners of the gang box are tightened down. (All the wires should be inserted through the back of the box before installing the box in the wall.) Connect the wires to the banana plug plates, then fasten the plates to the front of the gang box. I used the clamping version of the box, and I only had to make one larger hole in the wall rather than three individual smaller holes. The install looks as good as if someone who actually knew what he/she was doing did it.
