I would like to get a bike holder that fits on the factory rack of my '02 Protege5. Thule's catalog says they don't have any that fit; does anyone know who makes a rack that fits? Mazdastuff.com lists an attachment for the MPV. Would that work?

I use a Biketite on a piece of 1x6 and stand my Canondale Super-v up in the back.
The other option is to get a all metal rack (thats the wheel track with fork clamp)put it on backwards so the long end does not hit your 5 door. drill through you roof rack to have metal to metal

I used Yakima rail riders to attach directly onto the stock mounts. However, I modified the front mounts by drilling a hole in the center of the rail rider so that I can bolt it directly onto the factory mounts. You will need a button head 8mm x 1.25 x 20mm bolt to clear the hinge on the rail rider. Also, the rail rider clip will need to be hogged out to accomodate the bolt. I also re-used the stock covers and milled out an oval opening for the rail riders to give it a finished look. The rear rail riders mount directly onto the rails. The Yamkima racks are much better than the factory bars, and ultimately, I can now attach anything onto the roof rack.