On Gojira's last outing, I used a fabric screen pulled taut in a steel frame. The only problem was that because the fabric was pulled by elastic cord threaded through reenforcing rings in the fabric and through the metal, it took 2 people nearly 2 hours to put together.
For our most recent gig, supporting a Speak rally (for want of a better word), to promote Fairtrade and Trade Justice, I (with the help of the lovely Steve and Mel), redesigned the screen.

Basically what you can see here is the construction of the screen; the green represents a steel tube which runs through a channel in the fabric (created by folding it over and sewing it; represented by the dashed line). Then the screen is pulled taut by loops of elastic cord (red lines) which go around the steel bar and are then clipped onto the steel frame with the s-hooks (in blue). In this way and replacing some of the original hex-nuts in the frame with wing-nuts, the screen now only takes about 5 minutes to set up and take down; and if anything has more tension than it did before!
Sorted!
Apart from general tidying up, the next iteration will probably be to weld in place any elements that don't need to come apart.