thats really good thinking, but what i was thinking that a bunch of American vault dwellers, who have been taught American superiority the whole time emerge in Canada and they claim Canada(or at least the area) and all its survivors under their rule. this could be the capital Ottawa. also i was thinking that instead of one big map, there would be several spread across different areas of Canada and neighbouring US communities, through a convoy system that comes to areas every week or so, and stay there for while then leave for another area. you may need to pay with a unique currency in fuel or gain the favor of a major faction in the area. with the many areas opens up many possibities for conflicts across Canada from what TIberius said english vs french, and native conflicts. also i was thinking about the radio stations could play country music and rock cause Canada can't have been restricted like the States in music.
If they were doing a Fallout game set in Canada, it would probably be centered on Ronto. Pluses are it it's close to the US border (both Michigan and New York) and not outrageously far from Quebec (the front lines for thier struggle would probably be the ruins of Ottawa) so a variety of factions could be in play. The Regime in Ronto would...as Ashur hinted...have to be pretty tough to survive against potential enemies out of Detroit or Buffalo, not to mention Montreal. Any Vaults opening into this mess would probably be overrun fairly quickly by one power or another.
As far as music...there is a AM station in Ontario, out of one of the suburbs of Toronto, I believe, I can pick up at night that plays 40's Swing music of all things.