NC, I can understand your point about people not traveling, but think of it this way. The 4 BCS bowl games are well attended now, (Va Tech and Cinncinnatti being a rare exception). If the semi-finals are at pre-determined sites, you would indeed need to sell tickets to the host community long before the game. Save 10K per school. Give them up until three days before kickoff to sell them. If every several years Minneapolis or Atlanta or St. Louis or Tampa or San Diego or Detroit or San Antonio got a semi-final game, don't you think you could sell the tickets locally? Announce Monday that the Georgia Dome will host the national semi-final game next January 15 and see how many people will order tickets.
Then, the National Championship game, next year January 29, and only affecting two schools, could save 15 to 20K tickets per school and let the bowl site have the rest to sell locally for a National Championship game. I don't buy the argument that this will lead to empty stadiums.