Hey Kenny, this is good stuff.
I have a question about the chords Bob uses in Dark Star... using some pretty standard chords for A Mixolydian (A, G, Em, D, F#m) sounds pretty good, but still not quite as jazzy as Bob gets, esp. when listening to an early 70's Dark Star. I've tried adding 9ths and 11ths, keeping the notes of the chords compatible with A Mixolydian, but it didn' sound "right".
Do you have any specific exmaples? Should I be trying to find maj7, maj9, and/or maj11's rather than dominant chords?