This is what happens when you have too much time on your hands, and a really good geek budget. Meet Yoshi's Boxx.
Yoshi DeHerrera, one of the resident techie-neo-hacker-mod-gods who appears frequently on TechTV's Screen Savers has built the ultimate gaming machine. The video game wars are over folks. To truly have the ultimate gaming system, you have to build it....
The following systems are installed in the Boxx:
-Atari 2600
-Nintendo Entertainment System (8-bit)
-Microsoft Xbox
-Nintendo GameCube
-Sony PlayStation 2
-A custom PC.
Hit the above link to check out this masterpiece. It's pretty slick.