Sadly, no one can say for sure who would win with USC vs any of the teams you stated.
You just said quality over quantity; yet you state that the SEC has more bowl games.
A bowl game is a bowl game. 5-0 in bowl games is 5-0 in a bowl games. The BCS has always been trash and always will be. Like I said, a computer saying one team is better than another is bullshit. The only good thing about the BCS is the arguments it produces.
I say there isn't a team in the country that could beat USC in a bowl game. Period.