Parts wise it's a pretty standard Mini-ITX PC. However I've modified the front optical bay panel and the front of the case to accommodate 4 N64, 4 Gamecube, 2 NES, 2 SNES, 2 Dreamcast, 2 PS1, 2 Atari 2600/Genesis and 2 Saturn controller ports, all wired to USB with some breadboard between them. Hardware side they all function correctly with their respective controllers, but they're only ever let down on the emulator side by software glitches.
I built this early 2013, and because I currently have minimal space to work on projects where I live, everything modified was done with my trusty dremel, so please excuse some of the hackjobness. Once I'm home again and I have a proper shop to work in, I plan on giving it a fresh case and finalizing the wiring and making an overall cleaner setup. I also chose less than stellar parts for it since I didn't know whether or not I could even pull off the build.
Due to the tight space of the Mini-ITX size and the insane amount of wiring I had to do, overheating was a problem so a 120mm Slip Stream 2000 and inlet was added to the bottom of the case to help remedy the issue. All of the controllers' breadboard are housed in a project box mounted where the hard drive cage used to be, and the hard drive relocated to the unused optical bay with a mounting adapter. A Sedna 10-port internal USB hub is mounted to the underside of the hanging project box. The hub was used for isolating wiring problems so I could conveniently eliminate controllers I'd already finished. An automotive toggle I had lying around ended up on the back so I could control the red cathodes lighting up the case.
The dinky 40mm fan on the front obviously doesn't do much, it was never meant to. When I was designing the layout for the ports, I had an irritating space left over no matter how I repositioned the setup, so I added the fan to get rid of it. Originally it was going to be a 40 to 60mm adapter with a 60mm fan on the inside, but I didn't realize how little space I'd end up with.
Eventually the case and wiring will be redone, and soon I plan on upgrading the mobo and cpu with a Xeon E3-1231V3B 3.4GHz and an SSD.