I'm actually thinking your other scenario about Bayrou will come to pass, especially if Sarkozy overdoes it. I'm skeptical too of Sarko's appeal when is so explicit about the neo-liberal talk as was much of what he was quoted as saying in Le Monde today. Not so sure that appeals to as many traditional RPR-style supporters as one might think - after all, Madelin polls what, 3%, tops? However, it does appeal to a certain core Le Pen supporter. Certainly not all, but many.
I'm thinking Bayrou could surprise by mopping up some of those turned off by this neo-liberal rhetoric. I'm suspecting there will be more than a few. Fai de bèn a Bertrand, te lou rendra en cagant