I'd hate to see what's at the bottom of your list.
Let me ask you this: Do you honestly think that Bush would leave the GOP high and dry up to and through his second election without some indication as to his successor?
For a guy who seems to have an uncanny knack for anticipating, he would be a joke for not letting the party know that he's got a guy/gal in mind.
For what it's worth I think he'll probably let Cheney retire early and get Condi or Jeb or somebody to take the VP slot. Otherwise he's sold the party out bigtime.
Then again Michael Steele (Lt. Gov. of Maryland) has said he'd serve at the President's request in any capacity. Now that would rock.
If Steele is who I'm remember (spoke at the Convention last year?) -- he's absolutely awesome.