I won't even pretend to understand how the whole BCS ranking system will play out.
But LSU won't be playing for the National Championship.
In fact NO team from the SEC will be playing for it. (as far as I understand it)

Ohio State moves up to at least #3 after the weekend because Missouri plays Kansas tomorrow.
If Oklahoma knocks off the winner of that game in the Big 12 Championship the following week, that leaves OSU to move up to #2. Provided West Virginia takes care of UConn tomorrow.

While you can think LSU might woop some arse in the bowl games, it won't be for the Championship.

Scotto