Logistics for a Canadian Site
While I understand that there were many issues with customs, etc for the Trenton Rally, I'm sure the logistical nightmare can be overcome. If there is a convoy of MOA, vendors, suppliers, etc that come across the border at the same time in the same place (especially with the assistance of somebody like, say, UPS), the headaches could disappear. After all, NASCAR, F1, Indy Racing League and other racing series seem to enjoy coming to Canada on an annual basis. None of these organizations seem to have any sort of problem getting their cars, equipment, team members, souvenir trailers, etc into Canada and back. The first time NASCAR's Busch series raced in Mexico, all the teams met at the border, UPS had customs packages for them and away they went. 86 cars, parts, crews and swag.
What I am saying is that if there is a strong enough desire by the MOA, another Canadian rally site is possible.
If you want to consider a western Canadian site, the Camrose Regional Exhibition grounds have pretty much everything you are looking for. Lots of hotel space within and hour of the site for those who don't want to camp (seems to me the best hotel prices for Gillette were 40 miles away). Banff is 3 hours away. Other destination rides are close by. For those with lots of time, the Calgary Stampede usually ends the weekend before the MOA Rally.
Just my opinion.