I think I solved the riddle behind Madara's body. It's actually pretty obvious.
Check Chapter 487/Page 14
Let's say Madara stole the 1st Hokage's DNA in battle. He created Zetsu. Zetsu created new bodies for Madara in order to make him survive a whole century without aging. The only answer to that way of surviving the decades is a mind transfer technique like Orochimaru's. Nothing impossible so far.