Rudy has as much of a chance of being serriously considered as John McCain. Rudy was great for NYC and NY- but the Republican president can't be a moderate.
No one else comes close...
Rudy, while a good choice, may be on a collision course with the new Pope, who may insist that all Catholic politicans renounce pro-choice doctrine or leave the Church. That's gonna leave a mark whatever he does.