Gary Johnson. He was governor of New Mexico when I was growing up in Colorado twenty miles from the border, so I remember him pretty well. I doubt I'd agree with his economic policies at all, but this guy probably wouldn't embrace Bush's civil liberties program (though, truth be told, I said the same thing about Obama).
More to the point, he's a candidate I wouldn't regard as president with howling disbelief. I see the possibility of the loyal opposition.
So his candidacy is probably doomed.