Back in 2010 during the last big realignment, Texas, OU, Texas AM (or TT), and Ok State were going to the Pac10. Reports are that they were 30 minutes of it happening, ultimately getting curbed because of the LHN. A ton was happening at this time. This is right when Boise State joined the MWC. So BYU, Utah, TCU, Boise State were all in the MWC. If Texas/OU and others had gone to the Pac12, Utah wouldn't have gotten the invite there, TCU wouldn't have gotten the invite to the Big 12, and presumably BYU wouldn't have gone Independent. If the Big 12 remnants would have joined the MWC as Hair said, the MWC would have looked like this:

MWC 2011
BYU
Utah
TCU
Boise State
Air Force
Colorado State
New Mexico
San Diego State
UNLV
Wyoming

Big12 Leftovers
Kansas State
Kansas
Iowa State
Texas Tech
Baylor
Colorado (Pac10 invited CU with UU as a backup plan to TEX/OU)

Missouri, TAMU, Nebraska all left that year.

That's 16 members, and in those days, BYU/UU/TCU were always ranked, usually with someone in the top 10. The MWC was better than 2 of the BSC leagues for a few years by that time, so adding half of a BCS league to a strong non-BSC league might have mattered. Anyway, that would have been fun. Divisions probably look something like this:

Western Division
-----------------
BYU
UTAH
Colorado
CSU
AF
Boise State
SDSU
Wyoming

Eastern Division
-----------------
New Mexico
Iowa State
Kansas State
Kansas
Texas Tech
TCU
Baylor
UNLV