OK, just to keep the list up to date... I have found 2 more...
Source 1 had ...
Frieda Gessert
Elfriede Scherhaus
Sophie Gräfin zu Toerring-Jettenbach
Lonny Hertha von Versen
Source 2 had...
Karoline Bührer
Anna Scheermann
Source 3 ...I have found 2 more in the book "Unser Eisernes Kreuz"
Schwester Aust, who recieved it along with a personal congratulations from the Oberbehelshaber des Ostheeres GFM v. Hindenburg, so this puts it in December 1914 or later (She also later recieved a Rettungsmedaille)
Schwester Frida Schlenker, date unknown