I've been trying to find the article I had saved and have had no luck. Hopefully I can describe well enough... sorry if this doesn't make enough sense... it's from memory and it's been a couple of years since I read it.
What they did was attatch three metal pipes to the ceiling. I can't remember how they did it but it was in a way that the pipes could roll... ie - slid them through eyehooks or something... they did it two coming out from the wall parrallel from each other and then one perpendicular to that... so basically looking up it was a "C" shape facing the wall. You could size it to whatever space you wanted. To those pipes, they attached some plastic sheeting and rolled it up on each pipe like a windowshade rolls up. Then they put velcro along the sides of each sheeet. Then you could roll them down, and velcro the sides together, sort of closing it off. When you were done, you undid the velcro and rolled each pipe, thus rolling the sheeting up and out of the way until you needed it again.
Sorry for the crummy description. I thought about not even posting because I wasn't sure I could describe it well enough... but I thought it was a great idea when I read the article. I think it was a DIY type magazine article... if I find it I'll post back.
Rob