A few thoughts: If OU wins, KU gets the #1 seed, irrespective of the KSU outcome. Per the Star today:
If Kansas wins, it will do no worse than tie for the Big 12 crown for the second straight year. If the Jayhawks and Texas win, the Longhorns get the No. 1 seed based on their victory over Kansas.
If Oklahoma and Kansas State win (still with us?) there's a three-way tie and the Jayhawks get the No. 1 seed. The procedure in the tie-breaker is to separate teams from the same division. Oklahoma will have swept Texas. Then the Sooners are compared with Kansas, and the Jayhawks emerge because of their one-point triumph over Oklahoma on Feb. 5.
Probabilities according to Pomeroy:
UT/KU Win: 51% UT Win / KU Loss: 31% KU Win / UT Loss: 11% KU/UT Loss: 7%
This was a hasty foray into statistical analysis, so I could certainly be wrong, but I think this is right, and I'm comforted by the fact that the numbers add up to 100%