Just heard from the dealer: turns out it was a misaligned power window regulator...the technician said he had heard of this, though not actually seen one before mine...he's also a google monkey ;' )In any event, the dealership fixed at no cost and loaned me a GMC Envoy to tool around infor the last ...

My driver side window exploded about 1/3 of the way going up yesterday - had beenhearing the same clicking and rattling prior to that. The dealer so far is non commital: i'm supposed to pick it up tomorrow - will post what happens.