@Oepabakkes:
you can start here:
http://www.outofspec.com/frankenmac/wire.shtml
@Amigadave:
I guess I will mod my Quicksilver for an important reason: having upgraded this Mac with a Sonnet Encore 1.8 I had some problems, due to PPC 7455 overheating (and maybe higher power consumption too. I'm testing..). When the side panel is closed the Sonnet fit closely behind the Superdrive and the PSU, increasing heat problems and making the Mac hanging with a lot of default catch errors. This errors disappear when the Sonnet is cold (and wow! This little beast makes everything faster!!).
But you are right: the side panel of Powermac is a real commodity and so I found a case that do the same. More, the side panels can be both opened for much more comfortable access.