Keep in mind the conventions you just looked up are for members of the IPCPR. You have to be a broker, retailer, exhibitor and be a member to get in. Or just have a good hookup to get you in.

Badwhale-the reason they choose cities like vegas, new orleans etc.. is a lot of people that go to them choose that time as their vacation. When they have done the conventions at cities that aren't vegas like or have that wild tradition attendance is very low. So they stick with places that draw people to them as a city alone.