I searched Amazon for some heated mats and initially only found products that had really bad reviews.
Then I searched outside of Amazon and found Heat Trak. The reviews looked promising and while the return policy included a 15% restocking fee, I ordered a few just to try them out. If they worked, great - if not, I would only use one and return the others.
Well, no need. Check this out:
First time we used them, there was no snow but it was cold. We had people over and when they went outside in their socks, they were loving it - no boots needed!!
Then the snow came - sure enough - the mats worked perfectly. It's not instant - 2 inches of snow melts every hour but that's more than enough to get the job down. They aren't THAT expensive either (under $200 for a 5' mat)
Here are some links for Canada: