Wow...what a great idea. I have never seen such a thing. We've always scrounged fridges or chest freezers, but it would be really cool to design your own chamber and hook up the works from an old fridge or freezer.
I'd build it pretty much like a chest freezer, but designed to hold 6 or 8 cornelius kegs. I'd plumb in gas lines so you could use it to carbonate kegs. Maybe a space for two carboys to be lagering. Dang this sounds fun.
Keep us posted if you find any ideas or do any experiments of your own. Good luck!