Not sure if a Tour has been decided on a regular stage on the last day, but the famous Lemond TT ride in '89 did gain him the Yellow Jersey over Fignon. Lemond said that on the penultimate stage that Fignon had congratulated Greg on a good tour as if it was already over.... Laurent didn't count on aero bars and missing 58 seconds on the last day.... classic case of underestimation.
As for Lance only winning the TT this year, I think he may have gotten more satisfaction that Georgie and Paolo won stages for Discovery this year than he would have gotten from taking a regular stage... just an impression, though. Lance seemed so resigned to marking Basso and the T-Mobile boys that any other breaks were just let go. Hey.... 7 overall wins ain't nothing to sneeze at...