Another low-tech approach to consider is the periactoy, a three sided "flat" that is usually on casters. Lining up a few (3?) of them could easily cover 16 feet of width. They consume a lot of space, but you don't have to deal with the rigging each time. You can paint to your heart's content on a hard surface, and you have the option of three scenes that can be rotated into position quite quickly.

I gave up on rolling in flats as you suggest a while ago. Drops that have been painted more than once tend to get serious wrinkles in them, destroying the illusion.

The concept comes from ancient Greece. I have never seen it spelled that way before. I am sure, however, that the way I spelled it is an horrible "Americanization" of the proper spelling, and I stand corrected!

I have used three of them to great effect in a performance where one of the sides had a snug fitting door in it, and after the pieces rotated a few times (all in unison, timed to the music) the doors opened, and the actor/technicians who had been hiding inside hopped out and did a musical number. I don't have photos from that production, but the following link shows photos of a show I did where there was a single periactoi that was used to great effect.

http://members.aol.com/bmiller025/ThreeHotels.htm

The play takes place in three different hotel rooms - in Morocco, in the Caribbean, and finally, in Oaxaca, Mexico. The Periactoi served as a window in each of the three rooms. I was able to light each of the windows in distinctive, very different ways, to help create each of the scenes.

Joan, a few years ago, I did a professional production of The Phantom where they built these very ornate, beautifully-made rotating steel framed flats that spun around (maybe 3' x 8', and had interchangeable panels which could be changed from behind during scenes. It didn't work too well. The walls wiggled when the panels were changed, and it was very hard to prevent the walls from inadvertently rotating when they were being changed. A big distraction. Very cool concept, but it was too hard to pull off.

Dear Joan,

     I was on this site looking for info when I saw your post. We have successfully used a large format pipe and drape system for several years. We sew the 108 widths together to creat 18 by 40 ft backdrops then hang on the frame supported by adjustable poles. It is labor intensive at first but I can give you more info if you are interested because this is the closet thing we had until we got a theatre with a fly loft.