I'll answer my own question here. It does appear that there can be two "BCS busters" in the same year. From the wikipedia entry:
"The highest ranked champion of a non-BCS conference will receive an automatic berth if:
It is ranked in the top twelve, or
Ranked in the top sixteen and higher than another BCS Conference champion. "
http://en.wikipedia.org/wiki/Bowl_Championship_Series
I could actually see both BSU and BYU/Utah/TCU making BCS games this year. Am I reading this wrong?