Flying Flea HM293 is 14 feet long, but if you dismount the rudder (which i used to do on mine (HM14/360)) you get close to 12 feet. Sorry, plans not at hand now. The more retro looking HM14 is with rudder 13 feet. nIn link below you can find pictures of the most known models. By the way ... the plans of HM293 and HM360/380 are free to download in the same site. On other site you can find HM14 plans (also for free since the death of Pierre Mignet, we have permission to spread the plans).A Flying Flea must come awfully close to 12 feet, no?
Available models - Nest of Dragons