MS

Take a look at Tom Yost's site WWW.yostwerks.com He has a few shorter designs that may work for you. I assume there are ways to convert his designs which use very few plywood "ribs" to use of "conventional" bent ribs. One method that comes to mind would be to use his offsets to build stations out of scrap wood then build the frame complete with ribs using the forms, and when the frame is complete remove the forms. He uses a material that is basically a tarp for his "skins". The one issue you might run into is obtaining a glue that will work.
I hope this s useful.

John Van Buren