I always thought the smartest approach to expanding the classic hardware was not to monkey around trying to interface a bus (PCI) that's now obsolete. Instead, take advantage of the modules available for the embedded controller market, and host them on a Zorro card that's basicaly just a glorified clock port. You can get a module for ethernet that has it's own cpu to run the included TCP/IP stack. Same for USB host - even with mp3 playback. What else do you want to use on the classic hardware? Graphics? OK, can you get the specs on the graphics card you want to use? I'd rather try rolling my own in an FPGA, though I think that would be better interfaced to the CPU.