I too have been needing some sort of keyboard-reducing solution. I was thinking something along the lines of making an ADB KVM/switchbox kind of thing though.

I did come across this...it's a Next to USB convertor using an Arduino.

I thought about making a Keyboard II version just to use an old keyboard on a newer machine via USB, just for the fun of it. Seemed like an easy project. I picked up the parts, but haven't had the time to protoyype anything yet.