I've been thinking about getting the button hack for my empeg. However, instead of just going with blue, red, greed, etc, etc, I was wondering how hard would it be to adapt these and make them configurable in software.

I'm sure they would require their own PCB, and much more complicated connections and some sort of data bus to push them.

Yeah, the existing hardware scans the LEDs all at once I think, so you would have to do something different with hardware. I think those particular RGB LEDs might be a bit thick, depending on the placement you have in mind. You might be better off with one of the many SMD RGB variants.

BTW, Sharp also makes those DIP RGB LEDs which I have on order for a major project I am working on.

Stu