Martin Simpson does a great instrumental version on slide guitar of Cat Stevens "The First Cut is the Deepest".

There are indeed some rock songs which to the imaginative ear are just crying out for a folkie treatment. These are songs which ideally lend themselves to being played in alternate (alternative) rhythms in open tunings.

The one I am working on at the moment is "Whiter Shade of Pale", in Open D, but I have a feeling that Open G may work even better.