Somewhere I've got a bunch of sketches of ideas for a cab based on some Greene and Greene furniture. I was looking at something like a slope front desk (which is like a roll top desk with a solid panel instead of the rolling bit).
All the arcady bits and a flat screen monitor would be hidden behind the slope when you weren't using it as an arcade game. With a little engineering you could set up dual desk tops, one you CP and one flat, so that when you didn't want to defend the last human family (or whatever) you could unplug the cp, tuck it down into the body of the thing and put the flat desk top there to use as a computer desk.