interesting. Plenty of history there and with all of the new microbrews popping up around town, I think it would have some current interest.
Reds, Various Neighborhoods, Eastside/Westside, Transportation (River, Rail, abandoned subway) are all popular topics with rich history.
How about the history and evolution of the Cincinnati Fire Department. It was the first professional force in the country. A lot of history and has some cool old firehouses, plus I have to think the Fire Museum could give you some ideas and assistance.
Let me know if you need any more ideas or let me know if my ideas suck as bad as my assistance on Albuquerque did.