Vegas books are way too smart to offer 2 way props. Everyone holding those type of tickets could hedge. Obviously, Matchbook has a different business model with the exchange system etc.
Maybe late in the year if Ohio St is the only undefeated team -- you might see it in Las Vegas or at more offshores. I seem to remember seeing that type of prop on USC either last year or in 2005 but it was in early to mid November.