The German Futaba Dealer ROBBE are already selling 400 mm (15.7 in) antennas extensions for the FASST receivers. Must be soldered in yourself or specially ordered premounted with the receiver. Then the receiving part of the antenna can be mounted clear of the fuselage on most sized airplanes. See link from a Robbe dealer;
http://www.der-schweighofer.at/web/p...90&prodID=1281
These are said to be Futaba original parts so the US dealer should be able get these as well.
The range is said to decrease by 15-20%, but most likely this has no practical effect since mounting of receiver inside a fuselage will also decrease the range in the first place.