OK trying to keep this up-to-date with the results of my latest searches:
i845 chipset motherboards which have (or potentially have) PCPCI
QDI PlatiniX 2E/333 has solder pads for PC/PCI header. Got one recently, will solder header and test
Other motherboards from the PlatiniX 2 series, e.g. PlatiniX2-A which has the header already soldered
http://i.ebayimg.com/images/g/y6YAAOxy4 ... -l1600.jpg I found a few ECS motherboards that seem to have solder pads for PC/PCI header
i848P (cut down version of the i865PE with only one DDR channel instead of 2):
ECS 848P-A
http://76.my/Malaysia/ecs-848p-intel-so ... ailk@2.jpg not a great pic, the header is to the left of the battery
i865PE:
ECS 865PE-A
Both use the ICH5 southbridge, so it's a distinct possibility that it's really a PC/PCI. I have one of the above on the way and will be testing.