Hi
my writing is not about "value of german models" --- it is more about "rare models".
I live in Switzerland, Europe (south of Germany, north of Italy) - sometimes (not very often) somebody tries to sell an Big Indian "ULTRA-rare, high price" because it is an "Big INJUN" - see http://www.ipdb.org/showpic.pl?id=257&picno=41545 . Read the "Notes:" in ipdb about the South Dakota Indians complaining --- at that time Gottlieb simply decided to ship the "Big Injuns already made" to EUROPE (nobody complains - saving money for the company). So in the USA the Big INJUN might be rare - it is not so rare in Europe.
Really rare is the "Cosmint": http://www.ipdb.org/machine.cgi?id=4981 --- read the "Notes:" ...
Really rare is the "Red 'N' Go": http://www.ipdb.org/machine.cgi?id=6143 --- read the "Notes:" - ipdb does not write "story as the Cosmint-story" because: I know a person who claims "HAVE seen a slotmachine (like the ones in my JPG) having the name "STOP-N-GO" so the Swiss manufacturer made Williams make for the SWISS-Market: "Red n Go" --- we searched for a picture of the slotmachine - no luck - so ipdb cannot write the story ...
Really rare is the "Aces Top": http://www.ipdb.org/machine.cgi?id=5236 - I have seen one of them - the Backglass looked "original, not repainted" - I do not know a story to "Aces Top", greetings Rolf