The Performa 6360 uses a PCI card via a right-angle adapter and a wide slot opening on the back of the case. I noticed that my 6300, which uses LC PDS for expandability, also has this same opening on the back of the case.

I'm probably being outrageously optimistic here, but does that mean that there might be a way to shove a NuBus card in here via a special adapter?