Who will buy the extra supply in bonds once QE2 ends?

As the Fed continues its game and says it is happy enough to end QE2 come June, the question arises- who will buy the $75-100 billion in extra bonds once they exit the market? Europe seems to have its hands tied at the moment as does Japan and China has not been increasing its holding for a while either. That leaves who?

Any thoughts, ideas, opinions? Some are speculating that the Fed is simply bluffing (again) until in the end it makes up some excuse to continue buying in what will be QE3.