I'm surprised that no one from the UK has pointed out that some fine 6x6 and 6x9 folders were made there.
I'm not surprised that no one has mentioned that very good 6x9 folders were made in France after WW-II. If you're interested in learning about them visit Sylvain Halgand's site http://www.collection-appareils.fr/c...html/index.php , many of whose entries have English translations. Look for Telka (under D for DeMaria-LaPierre on the left side of the screen), Kinax (K on the left side), Pontiac, and Royer. The French regard Royer's 6x9 TeleRoy (Tele for telemetre, rangefinder) as highly as Zeiss-Ikon's 6x9 Ikontas.