I’ve heard that both the Libertarian and Constitution Parties have made overtures to Ron Paul. Regardless of what you think of his positions he does bring a large grassroots support base and fund raising machine to the table. I’m hearing that he does not want to run 3rd party because he’s done it once before (in 1988 for the Libertarian Party) and polled badly and he’s more interested in keeping the ‘movement’ going and if he ran 3rd party there would be a backlash as he’d be the Nader in this race to McCain’s Kerry and would catch the heat for losing the race for the Republican Party. Say what you will about Libertarians but the Republican Party needs there votes.
Besides, he has his House seat to defend and that is much easier within the framework of the GOP -- for now, at least.
If Paul won’t do it, who then? Keyes? The wya he is being utterly ignored and treated like he has no right to run by his own party, he might just be mad enough to make the race.