Hmm, I'd seen videos of moths, but nothing which clearly showed the rigging. That seems like exactly what I was thinking about...scaling it from about 8 square meters to about 15 would just be a matter of engineering, and figuring out procedures to handle a larger sail (I was surprised to see the standard Moth sail is just 8.0 m^2, as that would be a pretty ordinary size for racing windsurfers...I'm not much of a racer, but I've sailed 9.0).

Interesting that camber inducers are common on Moth sails...it seems that on the windsurfing side, cams go in and out of style as hemlines on dresses go up and down.

Following your lead, I did stumble onto
http://www.moth.asn.au/pocket_luff.html
and related sites; the linked site has a nice opinion piece about "pocket luff" sails (a more dignified name than "sails with socks" I suppose).

Perhaps a good followup question would be, what's the largest pocket-luff sail out there? Windsurfers usually go up to about 12.5 m^2, seldom much more.

Thanks for the tip!