What about the possibilty of organizing several events together. Here in North Carolina, they have the exotic animal expo, gun and knife show, power tool expo, and flea market all at the same time, in different buildings on the fairground, so you get a large number of people coming for different things, but looking at everything... I was going to suggest maybe having it around the same time as Sturgis, but then I figured 100,000 drunk bikers and reptiles might not mix too well...
Rob