Nice guide with some useful tips! These squared pillows are awesome. I think you can build such an equipment by yourself. Some games I play on my couch. Mostly mainstream console-like games which I can play with my wireless gamepad like Tomb Raider. A gamepad with cable is a bit faster but for casual games it's fast enough.
I don't like playing 3D-Shooters or anything where I need to aim precisely. I think the distance to my TV is the problem there.
But especially "couch coop games" are perfect for couch gaming (you don't say!!!).