Sorry this is long and not totally organized but I've been thinking about this and researching it for a while and I just started typing. Consider it like reading a blog by Grunkiejr.
GopherGod has it. Texas and aTm are tied at the hip because of funding from the state. It starts with Texas Governor Rick Perry being an alumnus of Texas A&M and continues in to their state legislature. There is enough aTm political influence in Texas that they would make it difficult for the Longhorn's to make a unilateral move to another conference. This was evidenced in 1993-94 when the SWC was folding and Texas started looking around for other conferences. From what I understand it was made clear to Texas that it would impact their funding if the didn't bring little brother along with them. Texas & aTm asked about joining the Big Ten but we had a moratorium on expansion due to the recent addition of Penn State. Next they went to the PAC 10 who was willing to take on Texas but Stanford vetoed the addition of aTm. Rather than joining the Pac 10 w/out aTm, Texas bowed to political influence that was working behind the scenes to bring Baylor & Texas Tech along with the two bigger in-state schools to bolt on to the Big 8, forming the Big 12. This left Houston, Rice, TCU, and SMU beyond because they didn't have the crowds or the political clout of the other 4 schools.
I personally believe the Texas and Big Ten pairing are perfect outside of the aTm connection.
1. They are considering starting up a UT Cable Network across Texas just like the BTN but that start-up is a lot of risk whereas the BTN has already fought those battles and proven success so we're a good match. Plus, a UT Network wouldn't get access to show Texas football making it an even riskier proposition.
2. Even though Texas gets a disproportionate amount of of Big 12 TV revenue (based on nationally televised games) joining the Big 10 and sharing proportionately would still increase their overall revenues based on current contracts. Expanding the BTN would make that even greater.
3. Joining the Big Ten would grant Texas admittance to the Consortium of Institutional Cooperation (CIC) which is the Big Ten Conference Members + U of Chicago. Being a CIC member would help them access federal research grants (they struggle federally and most of their grant money is state or private).
4. Texas isn't struggling for academic prestige but between #3 (increased research $) and joining a conference with much better academics than Texas Tech, Oklahoma State, Kansas State, etc it puts them in a better academic light.
For the Big Ten:
1. Texas guarantees distribution of the BTN to the Texas markets. The only non-Big Ten schools with a fanbase like Texas are USC (not happening) and Notre Dame (national fanbase so adding them doesn't ensure incremental distribution the way adding Texas ensures distribution in Texas)
2. Adds a premier research university that is already a member of the American Association of Universities.
3. Adds a powerhouse program to help the prestige of the conference.
4. Adds fertile recruiting grounds to the conference.
I think if it was just up to Texas and the Big Ten, we would have our 12 member. However, for reasons alredy discussed that probably isn't possible so the question becomes whether adding aTm is a dealbreaker for the Big Ten. aTm doesn't detract from the conference (good academic institution, decent athletic programs) but how much does aTm dilute the added profitability that Texas brings for the conference.
Personally, I think the numbers probably still make sense with aTm in the picture so I wouldn't be surprised to see us add both Texas, aTm and a third team to be a 14 team conference. In my mind the candidates for the third school are Missouri, Notre Dame, Nebraska, Rutgers and Syracuse. Each brings a new market for the BTN (Pitt doesn't bring a new market so I don't think they make sense) except Notre Dame who doesn't bring 1 direct market but hopefully allows the BTN to charge more to the cable companies for adding the sports package in non-Big Ten Markets.
Before anybody says Notre Dame will never happen I would like to point out that the Notre Dame athletic dept is the #14 money maker in college sports (much lower than most people would guess considering the NBC contract). Times have changed since ND turned the Big Ten down 10 years ago and now our TV contracts and the BTN are much more valuable than what ND has. The Athletic Dept at Ohio State, Michigan, Penn State and Wisconsin all bring in more money than ND and Iowa is actually ranked 15th on the money list, one spot behind ND. We can offer them much more money than they currently make but the question is how much value do they place on the adoration that NBC pours upon them for 7 Saturdays each fall. Notre Dame could easily become member #12 or member #14 w/ UT & aTm if they choose based upon the numbers.
If ND doesn't happen I'm not sure who would be #2 choice. Nebraska is the next highest prestige in football and would create a good rival for Iowa but they bring a small tv market, weak non-football athletics and they would be the weakest academic institution in the conference. Mizzou is interesting because St. Louis is actually a split-market w/ Illinois but they should add KC. Mizzou has never been a football power and they have been better in basketball but inconsistent over time. It is a better academic institution than Nebraska but would still be the worst in the conference. Rutgers or Syracuse could arguably help bring the NY market but it isn't a foregone conclusion. Both are good academic schools that fit in with the conference but neither brings great athletic programs to the table with the exception of Syracuse basketball (and historically football but they are the most similar to Minnesota in terms of past success that may not ever be recreated again).