PCI (no express) GPUs
You can actually pick up a PCI to PCI-E 1x (open end) adapter and plug in any video card you want. Then use a PCI-E 1x to 16x adapter. This is an example, but there are cheaper ones out there.

http://www.quill.com/startech-pci-cards/cbs/352874.html?cm_mmc=SEM_PLA_T_352874