I don't know much about the Boa system but I am in Toronto - you might want to try: Boardsports, Boardzone, Hogtown and So Hip it Hurts and see if they have what you are looking for. I would call first though before just showing up as I have been to at least two of them recently and can't recall seeing any Boa systems at all (now I was looking at women's stuff so the selection may have been different).
Alternatively you may want to expand your horizons to speedlace boots since the main advantage to Boa's seems to be ease of tightening and the speedlaces pretty much match that advantage now. Many of them have dual zone technology so you can tighten top vs. bottom differently. You will probably have an easier time trying to find these as they are very common in Burton and Salomon boots which are carried pretty much everywhere.