Stlill working on my simpit. I'm just making it up as I go, with limited skill but it's solid, comfortable and works. Need to make my CH pedals wider though, have room for it. The pit is cramped, which was the idea, and the centre stick feels right in height. I made the pit about 10 inches to small in width and had to cut the panel out near the throttle, but the shelf comes in handy and that's the wall side.
http://hamel.gallery.netspace.net.au/Simpit-Construction