I don't think it really qualifies as a true 'project', so I thought I'd post it here.
I recently bought a Kodak Zi8 camera, and have been making some videos, so I figured I'd document my first power up of my Dreamcast/PC adapter box on my New Astro City cabinet.
I built a project box that contains a Happ Universal Video Converter, a JAMMA fingerboard and molex connectors for controler input. The UVC gets power from the 5v and 12v off the JAMMA harness, and can output standard or medium resolution. The output of the UVC is fed to the JAMMA fingerboard, so it will display on the cabinet.
I have an audio amp although it's not a 12v car amp, so it needs to be plugged into an outlet. Not a big deal since the Dreamcast does as well.