The Pac-10's out of conference schedule was the toughest, plus they play an extra in conference game. The SEC's was the worst. It's easy to look good when you beat a bunch of nobodies and your average team is 8-4 (4-4).
Ranked teams SEC played (3 out of a possible 48 games for 6.25%): Texas A&M Oregon Florida State Ranked teams Pac-10 played (7 out of a possible 30 games for 23.33%): Iowa Oklahoma State Nebraska Wisconsin Nevada Boise State TCU BCS schools played OOC: SEC: 16 out of 48 games for 33.3% Pac-10: 15 out of 30 games for 50.0% (you could add another 10 for playing each other 9 games instead of 8)
Look at TennesseE. OOC loss to Oregon at home, and wins against UT-Martin, U of Alabama-Birmingham, and Memphis. Beat Kentucky, Vandy, and Mississippi, and you're 6-6. That is the Vol season. If Oregon State had played Eastern Washington instead of a conference game, they would likely be bowl eligible. They were stupid to schedule Boise State, TCU, and Louisville as their 3 OOC games. The SEC's secret is to rarely go on the road and to play a lot of OOC home games. Hell, the Ducks were smart enough to have an FCS team on their schedule, as was Auburn, and it hasn't hurt either team in the BCS rankings this season. OS's problem is that they can't sell enough tickets to cover the cost of bringing in a home FCS opponent.
OSU wouldn't have been bowl eligible because Eastern Washington is in the lower tier, so it doesn't count for bowl games. But you're right, if they'd scheduled someone like New Mexico, they'd be in a bowl game.
