I just arrived back from my trip to Canada - this is how I ended up doing it:
•.Didn't go the 3G iPad route, stuck with my iPhone.
• Tried to go to 7/11 to get a SIM, they had run out.
• Tried Rogers, they tested my phone and said it wasn't compatible.
• Settled on Virgin Mobile - it cost me about $50 for 1GB of data + a few calls / SMS. I was desperate at this point as I'd failed on my preferred options and time was running low. In the end, Virgin wasn't too bad. The reception was patchy and in the rare instant when there was 4G the speeds were decent. I was able to keep up to date with all of the work stuff I wanted to (chat messages, mail, etc) and even use Instagram, but I wouldn't dare say Skype was an option.
TL;DR Went with Virgin Mobile, they aren't great but good enough for email / chat when you need it.