Guitar making in Germany or maybe German speaking middle Europe would be more correct had a a number of focal points. Two major competitors were Schönbach (now in the Czech republic) and Marktneukirchen in "Sachsen" ex-East Germany. Then another group based around Vienna. No doubt there were other areas also - but these were the biggest. Somewhere in the Hessen region there was another group with some famous names but I don't know where the core was .
After WWII the "Sudeten Germans" became refugees with the result that the Schönbach music centre vanished and many of the people from that tradition settle in a new "instrument makers village" outside Nuremberg called Bubenreuth. GK Hannabach http://www.hannabach-instruments.de/
was one of the people who settled in the Bubenreuth area and became an apprentice to his fellow Schönbacher Arnold Hoyer and has had his own workshop since 1953.
I had the pleasure of chatting at length with the Hannabach's last year. Hannabach senior has actutally written a history of German guitar building but I don't know where it is available or where it was published. Post WWII The Buebenreuth area produced a lot of jazz guitars. Part of the reason was that instrument makers depended on the US military to help transport their belongings and materials from their old home to the new area and the deal were paid for in guitars - as jazz was popular, those along with cigarettes were the currency of the day as the German money was worthless. As a lot of the instrument makers were really violin and cello builders, carved top guitars were an easy transition. Hannabach is related to the Hannabach strings family - all sorts of family connections in the business. In the Frankfurt area the builders Brunswicker & Apelt are tow of the many builders who learned in that tradition.
Prior to WWII there was a lot of competition between Marktneukirchen and Schönbach and it may be that Marktneukirchen was more successful from a business perspecitive (not sure about this) and in fact bought in violins from Schönbach which they sold on as middle men. Today there is a museum in Marktneukirchen which I hope to visit at some point.
If I can track something more concrete down about and of the other traditions I will update.