Over the past week or 2 the american xm navtraffic has been activated for Toronto, Montreal and Vancouver. Note that this is only incident reports (accidents etc) and not yet traffic flow:

http://www.xmradio.com/navtraffic/market_coverage.xmc

I called xm canada and they have not yet activated the navtraffic in canada, but as far as I understand, if you have U.S. xm service with navtraffic it should work in Toronto, MTL and Van. Has anyone tried this yet? I think that all you need is an american address to activate via the U.S. xm network, unless our canadian bought G35's with xm are somehow linked only to the canadian xm network.