yup, it should produce a bunch of torque but at such low wind speeds it's not really that much. I can barely wait to get it finished and up on the pole, can you tell!?
If you're using 6" PVC, consider cutting 2 inches out of the pipe first. Here's a pic of what I mean...
Removing part of the blade seems like a bad idea but it's really not. 1 inch from each blade doesn't reduce the total area much but it does change the shape of the blade and it will give the vawt a higher top speed. Also, if you're going 10' tall, don't do it exactly like Ben's - you'll want bearings on either end at the least.
Read my "quick vawt" diary entry if you get a chance. The way that's put together makes it really solid and it spins like crazy. It should be able to be scaled up pretty easily too, it just depends on the pipe you use and whether or not the blades flex too much...but then you could add extra brackets to keep it secure in several places down the length...
..and now I'm rambling and pulling the post off-topic...ahh!