Rob Ford comes to mind for TO - in a positive sense. He was just so over the top, so ridiculous, that it made the city seem... approachable? Cool? Street cred?
I'd definitely include Gregor Robertson for Vancouver and Naheed Nenshi for Calgary. Both are widely known, both have been here for presentations. And Robertson is hot, so there's that.
Amy Pohler for Boston. She's great at promoting the city.