It seems that late last night, Zunited writer Josh Martin was able to successfully purchase and download a song from the Zune Marketplace in Canada. Normally, there would have been an error message of something to the effect of "not available in this region", but this time the purchase went through without a problem. Unfortunately, a lot of the browsing UI still isn't there, but the purchase itself seems like proof that the music Marketplace will be headed to Canada sometime soon.
This all could be one big bug, and the Zune music Marketplace will still be avoiding Canada, but if it does turn out to be true, it'll be a boon to smartphone users in Canada who currently only have the iTunes as an integrated music solution. With some luck, this could help spur Windows Phone sales in Canada, since Android still doesn't have an integrated music store, and the unofficial solution (Amazon MP3) isn't available in Canada.