There are several of the smaller glassworks in Bavaria which have escaped publicity. They have never been at the cutting edge of design, even though they produced items fully compliant with the taste of the day in the 60s and 70s; they just kept out of the publications. Names include Gistl, Wiesenthalhütte and Hirschberg - there may be others. Some of these stayed out of the limelight because they produced for better known traders like Ingridglas and therefore did not have a marketing department of their own.
Hopefully soon the full history will be made available by someone with access to the archives. For the time being, that is all the info I can give you....