Melanie,
I've never actually been to this studio, but almost everytime we go to visit my parents in Cincinnati, my boyfriend and I talk about going here.
The Step-N-Out Dance Studio sounds like a pretty good ballroom studio, and they have some very well-known and respected guest instructors at times. They are in Covington, KY, which is probably too far west to be easily accessible on a regular basis, but may be okay for an occasional trip.
Their website is at:
http://www.stepnoutstudio.com/index2.htm
Good luck finding instruction!
Sara