No Big East teams will be a replacement for Missouri in the Big 12 because of their 27 months hold with the SEC. Missouri say if they leave they will leave to play elsewhere in 2012, which means the Big 12 will take a team that can start conference play in 2012. Even if Missouri does not leave till 2013, the Big East teams will not be available till 2014. This is where BYU comes in and probably why they are still being pursued. BYU can probably start conference play in 2012 and definitely by 2013 if they choose to join.
If the Big 12 decides to take the Big East teams anyway, which is what I hope the Big 12 does and go to 14 ("Big 14" is owned by the Big 12) then taking WVU, Louisville, and Cincinnati would be preferred as a package rather than just two of the three, as along with Iowa State would allow for future regional play as well as concentration of geography within the B1F footprint. These three teams may not start Big 12 conference play until 2014, 2013 at the earliest. Thus i see an opportunity for a program to demonstrate its commitment to taking it to "Big 14" level. Such a program would have to start this year and demonstrate itself over the next year or two. Think of it as a provisional membership plan?
For programs currently weak in football play but with excellent academics, the program needs to show commitment to improving itself, partly through on field performance, but more so through building athletic infrastructures such as an on campus stadium of sufficient size and other athletic facilities, coaching hires and staffs, and general support from the institution to its athletic program (not just football). It may also be easier for a strong academic program to commit to academic because academic is the true raison d'etre for universities. If mission one is already accomplished, then mission two, brand building will come easier. For most university, brand building is easiest with athletics. If for simplicity rating programs for good academics uses AAU membership, then there would be three available AAU programs outside of AQ conference: Buffalo, Rice, and Tulane. Buffalo is probably too far away, thus leaving Rice and Tulane.
For programs currently strong in football play but weak in academics, it will need to demonstrate a commitment to improving its academic. This means faculty recruitment, grants awards, and quality improvements. Since most programs are likely doing what it can already to improve academics, I do not see these programs as viable provisional members. When you get down to it there is only one program in this category: Boise State. They have an excellent football program but relatively weak in their academic. I do not think Boise State can do much in the next few years.
Then there are programs lacking excellence in academic and football, but are decent in both. To build up both athletic and academic at the same time is a Herculean effort. They would have to be on the cusp, just needing a bit more time and a bit more resources. The only program that springs to mind is Florida International, strong in academic and in a good geography to build their athletic (Florida).
Another consideration is private programs vs public program. In this consideration the private program will have an edge. For a public institution to increase its effort for academic of athletic will require support from the state government and I just do not see this happening. With the current state of the economy, falling tax collection and government deficit, most state governments would be hard press to commit more money to athletic program building. While the state of the economy is poor for private institution as well, their alumni base may be better positioned tax wise to donate, as well as a desire to see their alma mater compete better.
In final consideration, if the Big 14 does consider provisional membership, the following programs have an opportunity and I list them in order: Tulane, Rice, Buffalo, and Florida Atlantic.