Not to pile on, but you're even wrong here again. The Big 12 bowl tie-ins are not locked into the standings either. I don't remember who played who or what the scenario was that put ISU in the Houston Bowl that year, but they were in the mix for a couple other bowls.
In fact, there was a situation late in that year in which ISU was going to get screwed out of the Alamo Bowl if Iowa was selected to avoid hosting a rematch in Texas. But Iowa was picked for the Outback bowl, while Iowa State had the whole issue with losing to Kansas.
Just for the record:
Last year
Texas Tech 9-4 (4-4) was selected for the Jan. 1 Gator Bowl over...
Texas 10-3 (5-3) who played in the Dec. 27 Holiday Bowl
Iowa State has just as much opportunity to jump teams, they just have to be in the right situation (not up against a Texas team for a Texas based bowl game)
I'm pretty sure there isn't a BCS conference that has their bowl line-up locked directly into order of finish.
ESPN - 2007-08 Bowl schedule - College Football
ESPN - College Football Standings, NCAA College Football Standings, NCAA Football Standings