I have to mention, I live in Nova Scotia and I just went through an exhaustive search for flours in preparation for making my NY pizza (I just moved here from Alberta, and unlike Alberta, there is no local wholesaler from whom I can easily acquire good high-gluten flour).
In the process of my searching, I found this article:http://tinyurl.com/28gca9
It's a general article on flour and gluten/protein content, but it's of special note for us Canadians--scroll down and look at the "Canadian Flour" subheading. Apparently the article claims that even Canadian all-purpose flour is relatively high enough in protein/gluten content to be used for those types of applications.
I was curious, so I went down to the local Atlantic Superstore and had a look. Sure enough, the protein content on the Robin Hood All-Purpose flour was 4g (out of a 30g serving size). That translates to 13.333333%--which is pretty high. Sure, a good high-gluten flour would be around 14%, maybe approaching 15% at the very most, but I think 13 and a third is close enough. As Pete mentioned, you can supplement that with gluten flour if need be.
Interestingly, I looked at some other flour varieties from Robin Hood ("Best for Bread", "Nutriflour", etc)....and they ALL had the same protein percentage. They differed only very slightly from each other in terms of things like fat content...so minor a difference that it would be negligible.
Also interesting--this has probably been discussed on this forum before, but I was unaware until I did some reading...this "White Wheat Flour", which apparently has the taste and texture of white flour but preserves the nutritious parts of the wheat such as you'd find in wheat flour. Robin Hood's variety is "Nutriflour," which I bought, and I also bought a "Stone-ground White Whole Wheat Flour" from a local mill here (Speerville).
I'm going to experiment with these flours (and I also bought some gluten flour from an organic foods place), so I'll see how these flours work in practice.