sounding with the chord fingers
I used to do this with my electric guitar (also played feedback) but not with the acoustic.
I was never 'that' good.
The second one also includes a bit of looping.
Phil Keaggy has mastered looping.
Check out
Phil Keaggy - "Off The Record"
http://www.youtube.com/watch?v=4EuZ0hXIah8
I know its not acoustic but have you ever heard of the Moog Guitar?
The Moog Guitar - Phil Keaggy (noisy video)
http://www.youtube.com/watch?v=vF2OwtdlTaM
Moog Promo
http://www.youtube.com/watch?v=b3SsYQrgcyA