They tried to get in touch with the Big 12 back when they were looking for either A&M's replacement (Tulsa's newspaper released some e-mails form it a while back to either the OU AD or President).
One of them was from the SDSU AD or Pres - seemed fairly friendly, like they knew each other or had met each other sometime before - and one of the topic's he mentioned/discussed was trying to gauge any possible Big 12 interest in SDSU.
Since that was all I really saw about it / from SDSU, I'm presuming thoughts/talks on the matter didn't go very far.