Some of the Dells support Pic by Pic.... that might work if space is that big of a concern. That way you can display two images on a single monitor. I only think thats possible on their 24 or 27" model. Their 30" do not support that.

I agree with Ellay. Best to get two boxes. Some of the micro ATX computers are almost laptop size and anybody would be able to stick one under a desk. Heck, even the mac minis might even work - no idea on their video cards though.... might not be good enough. Also would need a gig of memory.