George Hicks has done plenty of experimenting and recently wrote an article for 3D Flying mag. on SFG.

Full scale has also done a bunch ----search for non-planar wings.

"C" shapes and full circles have been proposed----not to mention SFG by fuselage shape and location of the 'wide point'. Although the non-planar shapes are about as aesthetically pleasing as bug splat.

The consideration of SFG has been around for quite some time and Pattern flyers have used it for years.