Want to put money on either or both halves on that? I'm sure that I can make it to Nevada so it would be all nice and legal.
As for a power-"sharing" agreement, there is no way that Lott will do anything else. Lincoln Chafee (or whoever the Democrats have lined up to leap) will leap by January 3 regardless of Lott's final status, and Lott is simply too damn weak to think of doing anything besides "share" power, especially with this hanging over his neck. Heck, the 'Rats are already demanding equal funding even though they only have 49 votes on paper.
As for McCain leaving, if he's truly interested in ensuring that President Bush is a one-term President (and I think he is), he cannot wait until 2004 to make his move. There is no way that he's going to unseat Bush on the Republican ticket, so that leaves either the 'Rats or a third party. If he's truly interested in occupying the Oval Office as opposed to simply making sure that Bush isn't there come January 21, 2005 (which I think is rather less likely), he has to become a 'Rat. That is going to take some serious "bona fides" creation, one that is going to take better than a year.
Even if he were simply satisfied with just knocking off Bush, he's going ot have to start really separating himself from the Republican Party. As I doubt that there is enough time to do the necessary filings only in 2004, that would strongly suggest that he would need to leave the Republican Party in 2003. Do remember that Bob Smith decided to try a similar route, and he did his bolt (and return) in 1999.