From Sing Out! Magazine, Vol. 42 #3, article by Ken Hunt (I've not included the full notes on each, and please forgive the lack of diacriticals):----------
A Beginner's Guide to German Folk Recordings
Steffen Basho-Junghans (guitarist): "Guitar Soli" (Takoma #8902), "Fleur De Lis 1" (Blue Moment rts #004) and Fleur De Lis 2 (#005)
Dissidenten (world beat): "Sahara Electrik" (Exil #5505), "The Jungle Book" (Exil #5516), "Instinctive Traveler" (Exil #5535), http://www.exil.de
Thomas Felder (Austrian dialect - Swabian): "Schwaebische Vesper" (Musik & Wort #900)
Hoelderlin Express (includes electric hurdy gurdy (!)): "Holderlin Express" (Akku Disk #3025), "Electric Flies" (#3028)
Hundsbuam Miserablige ("a key element in the scene"): "Hundsbuam Miserablige" (BMG/Lawine #74321 34211), "Hui" (BMG/Lawine #74321 47599)
JAMS (dance music): "Bastard" (Wundertute #146), "Bastardmusik" (#156), "Fisch" (John Silver #004) http://members.aol.com/jamsberlin
Klaus der Geiger (Klaus von Wrochem, fiddler & fire and brimstone street preacher): "Klaus der Geiger und die Kolner Strassenmusiker" (MiC #8853 2)
The Merlons (early music style): "Naked Nature" (musical Tragedies #12242)
Cathrin Pfeifer (accordionist formerly with JAMS): "Panico na Panificadora" (TonArt #005)
Christof Stahlin (songwriter): "Promenade" (Nomen + Omen #15)
Trio Grande (a quartet, instrumental): "Nabucodonosor" (Verlag der Spielleute #9005), "Bagage" (#9501), http://www.reichmann.de/triogrande
U.L.M.A.N. (dance music): "Acoustic Power" (RUM/Lowezahn #2122)
Wacholder (post WWII folk music): "In Der Heimat Ist Es Schon (Stockfisch #357.6009; 1994), "Landgang" (Stockfisch #357.6015; 1996)
Zapf'nstreich (instrumental): "MCMXCVI" (Pantaleon Records #10028; 1996)
Collections:
Bavarian: "Munchen" (Tridont #0899) and "Bayern" (#0196) - derived from recordings made ca. 1900-1940.
From the Rudolstadt world music festival: "Tanz&FolkFest Rudolstadt 1991" and annually (Hai Deck)
It's apparent that Ken Hunt was using "folk" in the broad sense, rather than meaning strictly traditional music. Perhaps you can comment on these, Wolfgang? Contact information for all the record companies is also listed in the article.
~ Becky in Tucson