Nope everyone who has at least one MD/PhD acceptance prior to 5/2/2011 should be holding only 1 acceptance by now, unless he/she got off the waitlist somewhere else post 5/2/2011, then there's a 2 week period for the person to decide but most people seem to make a decision fairly quickly.
However you should check with the schools that you are still waiting for. For the program that I am going to, they sent out a finalized student list a few days ago so obviously the waitlist will not be used.