I'm from Toronto. Buffalo definitely has the most fans followed by Dallas and Pittsburgh. There are a smattering of Cleveland, Oakland, Miami, and Green Bay fans as well. Of course, you always see a lot of jerseys for the "hot" teams. For instance, a few years ago, you would have seen a lot of Ravens, Colts, Patriots and Falcons jerseys.
There will be a small contingent of Miami fans. I suspect it will be 40% Bills, 15% Fins, and 45% casual fans who won't make any noise or care either way.