I won't pretend to know who is/isn't willing to come to the JAR or if any of these opponents would interest people.
Cleveland State,Youngstown State - If we are going to play a Horizon League (or similar level) team, let it be regional foes. If nothing else, you'd potentially draw more road fans.
Xavier, Cincinnati, Dayton - I'm guessing none of these schools will play us, but maybe if we offered a 2-for-1 or even 3-for-1?
Duquesne - Obvious connections to the staff there and I think would be a good, competitive game most years.
All in all, the options are unfortunately probably pretty limited.