Homebrew 68K Machine Has a PCI Bus
hackaday.com
hackaday.com
I recommend taking the time to go to the original writeup -- you can see all the soldering on perfboard!
(More seriously, it's incredibly informative if your understanding of homebrew busses is stil in the "shared CPU bus" era. The interface to 68k memory-mapped IO is described in the "First PCI tests" section.
The key resulting limitation right now is that bus mastering is not implemented, but I don't think this is inherently impossible on the 68k bus: Macintosh addon SCSI cards did the same thing, no?)