Yeah it's doubtful you'll find anyone willing to rent out a bike to someone as that opens them up to all kinds of liability if something were to happen. Say you get hit by someone - you could sue the owner of the bike, the person who hit you could sue the owner of the bike and you, etc. Most people are very hesitant to lend their bikes out even to good friends or family.
That said, I want to visit Prague some day and hit up Prague Power and the Alphonse Mucha museum. Good luck finding a bike, and if you do, head down south east of Columbus towards Mcconnelsville for all the good roads.