I would think that making a suit out of curtains would make it pretty heavy and non-breathable!
Just kidding; my attempt at humor as the night gets started...
I've always seen a lot about those Shannon bug suits, but I've never heard feedback on them. I'll be needing to know this too soon, as I want to go bear hunting in the spring within a year or two, and I know I'll need to do a lot of research before the purchase as well.