If your going through rotors like that you have a deeper problem. Closely inspect the play of the hub by removing the nut and seeing if it has any play. The other big one to check would be the calipers. I'm particularly intrested in what the old pads look like from the warped rotor. When you get them off post a pic and show the gearheads around here. I personaly would suspect a sticky caliper to beable cause warpage that fast. Your pads are key though, they will generaly point you to the problem.

Would you summarize what we're looking for on the pads. I'm having a rotor warped on the rear of an 03 but it'* not unexpected; the dealer turned the rotor at 34000 when the symptoms first appeared to get it out of warranty.

yup, what he said.
also inspect each pad to see if there is excessive wear on one edge.

Your pads and calipers are critical in dissipating heat. If it is a poor quality or glazed pad along with a sticking rotor that would explain why your rotors are warping.
Pads with rivets dissipated heat better than bonded ones although some of the newer friction materials out there cancel that out.
My Performance Friction pads have been excellent to date in wear and heat performance without even a trace of fading at high speeds.