General criteria for hosting a CanJam meet is for a city and it's members having repeatedly hosting a large Head-Fi meet with 100+ attendees at a decent venue like a hotel or small convention center, and having several Vendors attending as well (including out of town vendors.)
So, want to have CanJam hosted in your city? Get cracking on getting big meets together on a regular basis. It's fun all around either way.
-Ed