He probably has more of a chance at Mercedes or McLaren before Ferrari while Fernando is there.
But seriously why would he want to leave RedBull? They should be a formidable team for the foreseeable future.
Exactly, whilst Newey is designing the cars at Red Bull it would be stupd for him to move. Even if Red Bull produces the inevitable dud the next car will probably be quite a bit better going on Newey's track record.
I don't know about McLaren but Merc have already tried to get Vettel to sign for when his Red Bull contract expires. Given Merc's lack of progress so far I can see the Merc board pulling the plug over the next couple of years unless the 2012 car is an absolute stoater.
As for Ferrari, they'll want a No. 2 who is just happy to be in a front running team and will willingly play the team game.