Well, a fellow member gave me some good advice. He said to pull the car over the next time the a/c stopped, and check to see if the clutch was running. If it wasn't, then to carefully take something (I used a socket extension bar) to "nudge" the clutch inwards. If it caught, then there is too much "play" in the compressor/clutch, so removing a spacer would fix it. Guess what? That was exactly what happened in my case. As soon as I pushed the clutch in, it caught, and began cooling again----albeit for only a few minutes. This tells me that it IS in fact the compressor, rather than some sensor/switch issue. (I haven't decided yet whether to dissassemble the compressor and remove the spacer, or simply replace the whole compressor.)

Sweating in Virginia