The Driver's Seat. http://www.imdb.com/title/tt0071442/
Andy Warhol does the mannequins and Liz Taylor brings the batshit crazy. A pretty funny movie (and book) on its own, but, man, is this thing begging to be stabbed to death. Um, I mean riffed. Just don't wear anything stain-resistant. You've been warned! (This might be a good one for Mary Jo & Bridget, especially.)