Pac-10 Expansion Scenarios

The Pac-10 has mentioned that it is joining the Big-10 in being 'open' to conference expansion. The decisions made could lead to a spiral effect in all the conferences.

Big 10: Add Pitt (They have a good market, so they'll go for another big Pennsylvania school to balance with Penn State.)
Pac-10: Add Utah and Colorado. (They'll go for entering new TV markets with major research schools.)

In this secenario, the Big East, Big-12 and Mountain West would have to scramble for new teams. The Big East may go for Memphis to replace Pitt. They may not have many choices. With a large basketball-only portion of the conference, the Big East would have a tough time adding any additional schools.
The Mountain West would quickly add Boise State. Teams like Fresno and Nevada may be next on the list. With the loss of Utah, the Mountain West may have a tougher sell for a BCS inclusion. However, the formation of 5 'mega-conferences' may be beneficial. The Big East and Mountain West could form their own lose 'mega-conference', with the winner of each conference playing for an automatic BCS birth. (This would also provide a nice little bit of additional revenue, and help forestall demotion of the Big East.)
The Big-12 would have bigger conundrum. TCU would be an easy choice. However, with Texas Tech, Texas, and Texas A&M, the Dallas/Ft. Worth market is already covered. Thus TCU would not add any new markets. It would also create a mess with the south division. Another alternative would be to add TCU, SMU and Houston. This would revive the old Southwest Conference (minus Rice). This would allow for an all-Texas south division. Or alternatively, they could try to get Memphis (or even BYU.)

What should be the criteria for picking schools for a conference?
Some useful stats could be:
1) Home football and basketball stadium size and attendance. These are the big money earners for a conference. It would be best to have a team that could hold their own here.
2) Director's Cup Standings. This is an indication of the breadth of the overall athletic program. The Pac-10, always ranks high here. Having a team that fields teams in a large number of sports helps to keep all things viable.
3) Football and basketball rankings. A team that has good postseason runs to add the the conference coffers would be ideal.
4) Us News Ranking. Though there are a million gripes about these rankings, it does put an easy number on the quality of academics at a school. Most of the Pac-10 schools rank high here, so a similar academic heavyweight would be desired.
5) Non-overlapping TV Market size. This is a little more tricky. You can look at the local area and assume that a lot of the locals would be fans of the team. However, you also have to look at where the aluni and other fans are. For example, there are probably more Texas grads in Ft. Worth than TCU grads, thus there is little new market added with Texas and TCU in the same conference.
6) Culture, Synergies, rivalries and other intangibles. TCU could probably sell a lot more tickets to games vs. A&M and Texas than New Mexico and UNLV. BYU's conservative culture may clash with the liberal Pac-10 culture. The Pac-10 has schools in twos, thus adding BYU and Utah may be a logical fit.