[Arran]

Russ;
  AS you well know RCA had a firm lock on the superheterodyne patent, so the majority of non RCA superhets from the 1920s were either home brewed or sold as kits. Apparently there was a loophole created by a judge that allowed people to built their own or the sale of kits for "experimental purposes", but it wasn't clear exactly what level of assembly constituted a "Kit". The radio linked to definitely had Langhorn branded IF transformers inside, but I also noticed that it had General Radio made tuning caps, the front panel doesn't seem to have a brand name engraved in it (though it looks like the Leutz superhets didn't either) only knob functions. Did Langhorn manufacture this radio in whole? Was it a kit they manufactured? Or was it a nicely made home brew where the builder selected Langhorn IF transformers? In any event if you can identify the manufacturers of the other parts used in this set, assuming it was a factory built or kit set made by Langhorn, you could probably make your own, the front panel will be the hardest part to acquire even as a blank.
Regards
Arran