Gephardt has been doing this for 30 years to no avail. Lots of also ran Democrats do it. Hillary is good because of who she is. She can draw crowds and the media. Lots of candidates will invite her to speak.
Hillary is not likely to run in 2004. Is is quite true that a candidate who runs for president, gets the nomination and is defeated is pretty well out of the game. The odds of getting to try again are very slim. Only sacreficial lambs get to do it. There is never a shortage of candidates and the ones who havn't had a shot don't take kindly to those who have taken a shot and lost and refuse to get out of the way. Jimmy Carter, Mondale, Dukakis, Bush Sr., Dole and several others have found that they are at the end of their careers when they run and lose.
Nixon is about the only guy to run,lose,then come back and win. If Goldwater had not been such a debacle in 1964, Nixon would have never gotten a second chance.
Hillary is young enough to wait until 2008. The Repubicans don't have any good prospects for 2008. Hillary has her eyes on 2008. The odds say a Democrat will lose in 2004 and win in 2008. Hillary will play the odds.