I haven't heard a lot of the other rumors in this thread with Texas joining the SEC or OSU accepting the PAC-10 bid. Why would Texas join what is considered the most difficult conference in the nation when they could play in a division that would be more favorable to them?
IMO this would be fun to watch, at the same time, it could backfire for the PAC10. I think the Pac-10 IS the second strongest conference, however, their bowl record last year and USC's penalties puts it at a weaker position for recruiting compared to Texas or Oklahoma. There are still 3-4 teams in the PAC that can compete with those 2 teams but imagine a conference Texas and Oklahoma could potentially win every year. Much better move in my opinion would be to take Colorado and dissolve the MWC, that is an up-and-coming conference, they could add Utah, BYU, TCU and look @ Fresno and/or Boise/Hawaii from the WAC and have the newbies in a position where they would have to adopt some of the PAC-10 style / educational requirements to mold them into PAC-10 members. Instead you're courting Texas and they'll do what they want regardless of their conference.
I have a lot of respect for the Big-12 its a great conference it certainly went 2-0 against PAC-10 in the bowls but the PAC is a great conference and its best years are still to come. This would be a nice move for all parties involved but like I said geographically, style-wise and common interests could mesh better if the above teams were added. (Yes, I know Boise has horrible academic standards and BYU is a religious school, but get them into the conference under conditions that mitigate these facts and you're in business).