Normally the demo for NCAA Football pairs participants from the national championship game, and the latest one, releasing next week, still does. It just features the combatants from the 2003 BCS championship game. Update: Plus six more teams.
Pasta Padre is now reporting that there will be eight teams total, citing additional information from an unnamed source. The reason for this is to showcase the new authentic offensive styles added to the game. The other six schools aren't confirmed, but the four matchups will be hardwired, so you can't play Ohio State against anyone other than Miami, for example.
Also, the demo will arrive on the PlayStation Network the same day as Xbox Live, which is Monday, June 14. The original post follows.
The reason for this seems to be in the threads the teams are wearing. Six screens for the demo published today show Ohio State and Miami in their new Nike Pro Combat getups. At first I thought the Buckeyes were threaded out in the the heritage uniform and helmet it's used in nonconference games early in the season, but the pants are different. Notice also both sides are sporting new Nike kicks, part of some branded apparel and gear upgrades (such as the leg brace on the Buckeye in No. 3) new to this game.