Taking a look at the map, you can see Syracuse and Rutgers aren't even close enough to be on it. In the west, we have Kansas and Kansas St -- not likely one will leave without the other getting an invite as well, so let's assume they are out too.
That leaves Nebraska, Missouri, and Iowa St on the western front. Nebraska and Missouri both look good, but Iowa St (as was said) doesn't bring a whole lot, other than location.
In the east, we have several Ohio-based schools: Ohio, Bowling Green, Cincinnati, and Miami. Ohio and Cincinnati don't offer much, but Bowling Green and Miami aren't so unreasonable. Pennsylvania is a bit east, but with Penn St there, Pitt all of a sudden doesn't look so bad either.
I would think realistically, the schools that the Big Ten would want would be Nebraska, Missouri, Bowling Green, Pitt, and of course - Notre Dame. And us hockey fans will keep pulling for Notre Dame, Bowling Green, or Miami -- to help push a return of Big Ten hockey.