Just my thoughts
Here's a way to split up Canada for forums:
Do all the Atlantic Maritimes together [Nova Scotia, New Brunswick, Newfoundland and Labrador, and PEI] because they are always together and it looks like they will be sharing an emergency radio system hopefully by 2012.
Next, do Quebec all by itself because, you know, they are a Nation within a Country and shouldn't be paired up with any others. They have their own ways of doing things, and they will surely remind you of it too.
Then to Ontario. There is so much going on there they should stand alone. They are where the Federal government hangs out and that keeps everyone busy.
Next, you have Manitoba and Saskatchewan. They should be done separately. They have their own Providence wide systems and there are some true scanner people from both Provinces.
Now comes Alberta. They are a Province in their own world. Alberta is the Texas of Canada, vast ranch lands and oil cities, cowboys at heart.
And don't for get B.C. in all her majestic beauty. They are the vacation spot of Canada both summer and winter. In the summer, lots of activity on the coast and the winter, great ski and snowmobiling action, and the dreaded avalanches.
Last are all the Territories where land is great and people sparse. They stretch from East to West and to the far North.
This is just my view on how to split up Canada for forums. I've lived here for the last few years now (from the USA) and this is how I see and feel how Canada forums would be if they were thrown up in the air and the people started grouping them on their own. It just seems to be the natural way that it would all fall into place all on it's own.
I do hope this will help you some in your search of how to split things up.