With interest I've read your message. It seems to me as a little local limited, limited to the province of Thuringia. I know Thuringia, it is the neighbour of Saxony, and I've lived sometimes in Thuringia. The mentioned "two villages" I dont know. There is no village named Klingenberg in Thuringia. You write about "Topographisches Worterbuch des Grassherzagtums", with any change of letters it may be "Topographisches Woerterbuch des Grossherzogtums", (Topographycal dictionary of Grand Duchy). Grand-Duchy is also a sign for a thuringian county.
The Family Name History for Klingenberg / Klinkenberger your father has purchased, is it sold officialy, may I also buy this? It seems to be interesting.
I think that "derived from the place where the original bearer once lived" and the meaning with "ravine mountain" is right, also the indication for Konstanz (and I see no difference between Klingenberg, Klinkenberg ...). You write "Bearers of this name are most numerous today in the mountainous regions of Germany, that is, in the south of the country, along the Alpine mountain range". That is not correctly. There are many many more Klingenbergs in the flat-lands of north-germany. I think that there are two origins at least. I've wrote about this and I'll write more.