If you use a capo on the third fret,then play a "C" shape chord,you can play the tune itself by hammering on/off,staying in the chord shapes.Pastures Of Plenty,which I believe is in D,is another song where you can keep your fingers poised above the strings,in a "C"shape,then you chord without moving your finger possitions.
I play this using a "G"harp
Don't know if that made any sense!
David