I predict and hope that Alan Mulally will not only become a board member but possibly co-CEO. It's not impossible. Whole Foods had co-CEOs for a while.
It would fit here as Elon needs to be in charge of anything product related, but someone like Alan would be great for earnings calls and can provide alot of high level oversight and insight into manufacturing. He's a west-coaster and gets tech (on google board), Aerospace (ran Boeing), and of course cars (Ford CEO). He gets the pros and cons of alternative energy/propulsion and he seems fairly pro clean energy.
As co-CEO it would give wall street the "adult in the room" they've been looking for for peace of mind. And I think Alan and Elon would get along just fine; Alan can go w/ the flow. It would give Alan a hand in helping to redefine the entire auto industry. Elon needs help w/ this.