Getting close to a source for f85r2

[ReneZ]

The other thing that took me a bit of time to check is my 'favourite' MS with the handwriting similar to the top of f116v.
This is MS Pal.Germ. 647. The You are not allowed to view links. Register or Login to view. says:

nördliches Oberrheingebiet (Lokalisierung nach der Schreibsprache)

I interpret "Oberrhein" as the part of the Rhine that is close to its source, which is the border between Switzerland and Southern Germany. This is similar to the area given by Welker that you quoted, but it should be north of that.
That could include Strassbourg - Freiburg, I suppose, however: it does not says that the language of Pal.Germ. 647 is Alemannisch. 

I have a note saying 'Südrheinfränkisch' which I must have taken from one of the Heidelberg library resources.
This You are not allowed to view links. Register or Login to view.  gives the geographical distribution, which may be the modern one (?)