That's because AMD is buying as many of the original stamping dies as they can get their hands on. I called AMD a while back and much to my surprise the owner answered the phone and after talking with him for nearly a half an hour he explained the purchasing of the dies and the licensing things he has to do to produce the quality pieces we all need.
He wasn't sure at that point if the A body stuff would be worth the trouble, as he wasn't sure about the market for them.