I took a different but slightly similar route than what I previously thought.
I purchased the components to make up a roller blind, just not the actual blind. The room is approx. 11' wide, and I have two 5.5 sections of 1.5" dia aluminum tubing. I'm going to get a 2, possibly 3 foot wooden dowel and put an equal amount in each section of the tubing to prevent it from sagging in the center. With the clutches/brackets I got, it can hold up to 16 pounds. Doesn't seem like much, but the screen weighs hardly anything.
I figure I'd attach the screen using black adhesive tape, and I'd also run it along the sides and bottom.