If the Pac 10 expands, Colorado is just about a lock to jump on board. Colorado is an AAU school, as is USC, UCLA, Cal and Washington. Colorado has more academic projects with Pac 10 schools than they do with Big 12 Schools. Colorado's Administrators speak glowingly about the Pac 10 and basically have told the Pac 10 that they are ready to jump, as soon as requested to.
This makes perfect sense for the Pac 10 also. Denver is the 16th biggest T.V. market in the nation. It also opens the door for a Pac 10 Championship game, if the Pac 10 also adds Utah, as expected. The Divisions in the Pac 10 would be clear cut. The North would consist of the the two Washington and Oregon schools, plus Colorado and Utah. The South would consist of the 2 Arizona schools and the 4 California schools. The Pac 10 would then revert to an 8 game conference schedule, which would include 5 games against their division foes, and 3 games against foe from the other division, ala the SEC, Big 12, and ACC. This alows for one more non-con game to be added to the schedule, and can make life a lot easier for borderline conference teams trying to get into bowl games.
I would really be suprised if this deal is not completed by the end of the year. While the Big 10 is grabbing all the headlines about what they may or may not do, and the SEC is quietly watching and threatening actions on their own, the Pac 10 seems to have their immediate goals set. The Pac 10 even has contingency plans if they want to expand past the 12 school number. Those plans include, Air Force, Colorado State, UNLV, San Diego State, and BYU, in effect, ending the MWC.