Xbox LIVE Gold For Less | One Month Free | Jack Link's Deal - Xbox.com
This worked for me, even in Canada. I actually was only able to get 4 months out of it. It extended my subscription online, and I received the confirmation emails. (Need to do this one transaction at a time)
My co workers weren't able to to do this after I did, so the amount of times you can do it may be limited by your IP address.
Standard M$ auto renew BS applies of course, but that can be canceled by calling, or renewing manually with a different subscription.
Edit: Seems to be dead now.