http://politicalticker.blogs.cnn.com/2008/01/03/supreme-court-justice-bill-clinton/
CNN's Political Ticker reports on rumors that Hillary Clinton might nominate Bill Clinton for a Supreme Court seat if she wins the White House. That would be quite interesting, and not without precedent; William Howard Taft served on the Supreme Court after leaving the White House. He's at least minimally qualified for the job, having gone to Yale Law School and been a law professor before entering public life, but he has neither lower court experience nor a track record of legal scholarship as is usually the case.
I doubt that this would happen, however, the smartest thing they could do with Bill is name him special envoy to the Middle East. For all his flaws, Bill Clinton is an excellent diplomat and he is still very well respected around the world and particularly among both the Israelis and the Palestinians. He really could be very useful in helping with solutions to the conflicts there.