I'm afraid this one is too risky to try because of another chip on the board, we don't know how good the compatibility with XP will be, it's mostly for modern mobos' and/or laptop/notebook's low power PCI-E version. I used a similar one to extend it to a "normal" PCI-E, after I decided to try to run my old laptop with an external GPU (they produce them in several variants), it worked only at PCI-E v.1.1 speed, so I'm not sure it will fit Dave's goal. In theory looks good, though.
EDIT: Just measure the space around the PCI-E, that USB stick is huge.