Thanks for the additional input! I decided to re-dish the wheel after reversing it in the frame and finding that it was offset in the opposite direction (wheel off center, not the frame).
So then, just to keep life interesting, air starts leaking from one of the spoke holes! Lesson: always get new rim tape with a new rim. Anyway, I'm glad it happened right there in my basement and not a few days later a few miles down the road.
Rich