ssrjim says:
The only issue I see is a lot of waste and extra cost.
Although there would be a lot of waste, not appreciably more than using solid plywood sides. They would probably still have to be skinned on the inside at least. Besides, the real reason is my lack of confidence in keeping the sides straight with thin plywood and a pine frame. By using this method, I am virually guaranteed a nice, smooth sidewall. As far as cost, relatively minor increase over using thin ply and pine, unless I used furring strips and hand selected them for straightness.
I have done some more drawing. I don't want to upload them, because the detail is lost at 640 x 480, so please follow my link. This design will allow me to put a 10 foot Weekender on an 8 foot trailer. Thanks, Mike, for the weekender design, and Joanne, for the great ideas from your build!
http://picasaweb.google.com/cliffneff/TeardropShots
Cliff