DIY background stand: fail.

I started a project today to make a do-it-yourself stand for the 9-foot seamless paper backgrounds I bought from a woman on Craigslist. Unfortunately, I've decided that the PVC just isn't quite strong enough to hold the background paper, and a bit too clumsy to be useful. I was basing it off of a  DIY Background Stand Design I found. I expect that the instructions would work well if my paper wasn't so heavy. His design uses 4-foot wide material, but mine is 9 feet across, so I expect it's quite a bit heavier. The weight, coupled with the extra width makes the whole thing unstable.

So now I have 40 feet of PVC and a bunch of couplings. I guess I could make some simple light stands. Anyone have other ideas?