Let's hear it for Cornelius Heinrich Dretzel:

http://www.jonathanbhall.com/dretzel.html

Not the only candidate - Kellner was the favourite when I first heard about these doubts - but that's a pretty persuasive stylistic point. And in the process Hall seems to have revived a nearly-forgotten piece well worth reviving. (He credits Isolde Ahlgrimm with the first step in the identification - never very well known in the UK, she was a terrific harpsichordist; an EP of a Bach harpsichord concerto by her with Erich Fiala was one of the first records I ever bought, and I've still got it).

And we can add Davey Graham to the list of acoustic guitarists with electric habits.