About a decade ago, we had a situation where many of the apparent candidates for the BCS lost in the final weekend. Ohio State was clearly "in", but WVU was upset and fell out, and someone else I think lost as well. LSU had lost the week previously to Arkansas and had two losses, but won the SEC.
We COULD have another year setting up along those lines. It's not hard to imagine the P12 champion with 2 losses. We could also see Texas/WVU upsetting OU with two losses. ND could still lose of course and be 11-1. NW could somehow upset Michigan and win the B1G with a lot of losses. Alabama could get upset by say 10-2 Georgia. Clemson, well, they look pretty likely to win out, but imagine somehow VT beats them in the CG.
There are all sorts of scenarios whereby this year could be epic.