Why not? The BCS in all of it's glory almost makes it impossible for a Big Ten team to go undefeated and not reach the National championship game. But lets not blame the BCS. Before it, college football has always favored the Big Ten. An undefeated Big Ten team has never not won or at least shared the National Championship trophy in modern history. The Big 10 has 2 teams that would be able to compete in any other conference in the country. That shouldn't be enough to guarantee you a BCS birth.
Penn St has 2 games left on their schedule that they could possibly lose. Ohio St and Iowa are those games. But Joe Pa's playing both games at Happy Valley.
There are are only 2 other teams that can spoil Joe's party, Texas and Miami. Texas will lose a game and even if they don't, they don't have a strong enough argument. Texas has a strength of schedule ranking of 84. Penn St's strength of schedule is 61. Texas won't go undefeated any way. They will drop a game against either Oklahoma, Oklahoma St, Kansas or Texas A&M. The only other team that can knock out Penn St is The U. The University of Miami bolstering the hardest schedule in the country should make the National Championship game even with one lost. But, I will wait to argue that at a later date. For Joe Pa, a National Championship game farewell tour would be fitting for a guy who has coached for a 1000 years. p.s. it should go without saying that they'll be playing Florida.