First, every conference game will be on either a Fox channel or ESPN -- BYU would not have to worry about playing on "local channels" because only OOC games will be saved for the local contracts -- typically a game against an FCS or Sun Belt/MAC team. I'm going to disagree that FX is like Versus, from what I recall seeing of TV ratings, the Big 12 games on FX have had similar ratings to BYU's games on ESPN (in the 1.5/1.6 area). As for games that are on Fox regional, you can get that "regional game" everywhere in the country, you likely just have to subscribe to a sports package which gives you the various sports regional packages.
As others have pointed out, we are only guaranteed 3 games in ESPN (ESPNU not included) and, with the team playing as it has been, we won't be getting more than that on ESPN in the future. And, just like now, our away out of conference games are how we contract them -- that doesn't change just because we are in the Big 12.