>>What happens if someone took out Romney after he is elected but not sworn in? Is Ryan the President???
It depends on whether the electors have voted or not. If not, the Romney electors would get to pick anyone that constitutionally qualifies- Ryan included. If they have, Ryan would become President pursuant to the 22nd Amendment.
If I was an elector in that case, I'd urge for something like a Gary Johnson / Ron Paul team... just to shake things in DC up.