OU/OSU aren't bluffing. Larry Scott wants the OU brand badly for football, yes we arent a big market but we are the bluest of blue bloods in the sport.
I don't doubt that Larry Scott wants OU in the PAC-whatever. But I still have yet to see a reasonable explanation for how Larry Scott is going to sell Arizona & Arizona State (and also Utah and Colorado to some extent) on voting for further expansion when they get placed in a division which severely severs their recruiting ties to Cali. ASU & UofA do not want to be placed in a PAC-16 East Division where they won't even play a football game in California on a yearly basis.
Unless things changed when they expanded initially, I'm pretty sure that all members of the PAC have to vote unanimously to expand. I'm not so sure ASU and UofA are going to eagerly take one for the team to welcome the Sooners & Cowboys.