None of what you are hearing on
  Twitter about Texas or the Big 12 expanding is true. Some of what you are reading has at least a partial basis in fact, but most of the chatter is just recycled rumors recited over and over again until they take on a life of their own.
In early October the Big 12 thought it might
  be forced to expand in order to have a conference championship game. Their
  expansion committee reviewed financials submitted by Cincinnati, UCF, USF
  and UCONN.
Fox and ESPN were part of the
  appraisal and they decided that none of the candidates offered enough value for
  consideration without impetus from the playoff committee. 
That’s not an insult
  to the programs mentioned. None of them having been playing FBS football for
  that long and none of them have the track record of success the Big 12’s unique
  requirements demand - at least not now.
The Big 12 decided to table the idea
  of expansion until they know, for certain, the exact  formula the playoff committee
  will use. They have been told their lack of a conference championship game will
  not hurt them, but until the exact formula is revealed they can’t be sure. They
  should know sometime over the summer. 
Why wait? Isn't money the motivation for everything expansion related? 
If the Big XII
  expands with any AAC school they take a pay cut and none of the Big 12 schools are willing to see
  their revenues reduced unless they have no other choice.  
Again that’s not a slight to
  Cincinnati, UCF or USF. That’s the reality of the last ten years of television
  ratings for each school. 
I understand the huge demographic
  market area of Ohio and Florida. I covet the deep recruiting base of both
  states for the Big XII but the conference doesn’t need untapped television
  markets. 
They don’t have a conference-wide
  network to monetize additions for market share alone. They can't justify expansion with carriage or affiliation fees. They need big time programs with a history
  of winning. They need marquee match-ups for primetime that generate Nielsen
  ratings to justify advertising dollars.  
Here’s the problem for the expansion
  candidates: without using market size as a factor the value of school’s
  football program is hard to quantify. TV ratings, merchandising, licensing,
  ticket sales, win-loss percentage and bowl performance become even more
  important and those factors are quantified over decades not years.
Expansion for the Big XII is only justified if programs with a national
  reputation that appeal to national television audiences are added. They need name
  recognition in a program, not demographics, and none of the available
  candidates has the cachet necessary to punch their ticket into the Big XII.  
At least none that are on the East coast.
  BYU fits the bill on most counts in terms of program prestige, but the Cougars
  are reluctant to give up their own deal with ESPN especially when it means they
  can keep Sundays sacred.
The other candidates are all deserving
  programs but none pass the Big XII’s litmus test.
Add BYU, Cincinnati, UCF, USF, UCONN or
  Boise State and the revenues go down and that’s a deal-breaker right now for
  the Big XII.
Expansion is a dead issue… unless the
  playoff committee decides a conference championship game is weighted in the
  formula used to select playoff teams.
  
  If that happens the Big XII would expand to
  at least 12 by adding Cincinnati and BYU or UCF.  
How likely is that scenario? Not very,
  according to those in the Big XII. They have been told they will not be
  penalized for their lack of a championship game.  
Is all hope lost  for Cincinnati, UCF,
  USF, UCONN and BYU?
  No. The exact formula the playoff committee
  will use hasn’t been finalized.  If
  a weighted conference championship game makes it into the formula the Big 12
  will move quickly to get to 12.  
Remember the review the Big XII did of
  candidates back in early October I mentioned earlier?
  A lot of the rumors floating around Twitter
  and message boards come from those evaluations. People hear that a few schools
  submitted paperwork and jump to conclusions.
Here's a confession: back when WVU submitted paperwork to the SEC I jumped to conclusions too. I assumed that a school wouldn't submit financial documents to conference unless it had been accepted.   
I didn't have a full understanding of the process then but I know now the submission of financials is just the first step.
 The process is officially called "due diligence" and it's not a rubber-stamp. Factors are included in the submissions like budgets for individual sports and projects on facilities upgrades and such. They also contain information like ticket sales, merchandizing and contributions that are vitally important to the appraisal.
These documents are complex and many people within the schools are needed to compile all the information that's needed. The people who help assemble the packets obviously know what they are for and human nature takes over.
The problem is they only know about the submission.
The fact is that when a school is
  told no or “not now” it’s kept very quiet. In many cases only the president and athletic director know the outcome.  And the people who helped prepare the documents -- all they know is their school applied to the Big 12 and everyone knows you don't apply unless you know you will be accepted. So they naturally jump to the conclusion that submission means acceptance and that's how rumors are born. 
  
The other factor is the real
  unhappiness at Texas. There is a small, but very vocal faction, of Texas
  boosters who are jealous of the publicity that Texas A&M is receiving. They
  blame the Big 12 for the Longhorn's recent woes. Fortunately there are those at Texas who understand the real
  problem is an aging coach who has lost touch with the kids he must recruit.  
Yes Texas had discussions with the
  Big Ten earlier this season. Both evaluated the grant of rights and decided it
  could not be circumvented and ended their discussions.   
I’m aware of the rumors that Big Ten
  lawyers think they have found an out for Texas. The Big Ten may have identified
  a weakness in the Big 12’s grant of rights. That’s unlikely. The grant of rights
  signed individually by all ten members of the conference is a simple legal
  instrument that relies on case law for its weight.
The very nature of its simplicity
  leads to divergent theories on circumventing it, but the undeniable fact is the
  any legal battle over the grant of rights is almost certain to take longer than
  12 years.
The other certainty over any
  potential legal battle: the court would enforce the rights holder’s claim until
  complete adjudication.  
The risk is just too high for the Big
  Ten. They could challenge the grant of rights, incur huge legal fees and lose and all the while the Big 12 would retain the rights to broadcast Texas sports and the money derived  from those rights.   
The Big 12 would not settle. Six current members would be fighting for their conference and their seat at the table. They would not disband for the same reason.  Jim Delany knows it would be a fight to the death. 
The other rumor about the Big Ten: the one
  that says the Delany is still watching the outcome of the Maryland suit very
  closely - keep on eye on that one. I haven’t been able to verify it
  yet but on the surface that one has teeth.