Very interesting exercise ... although, to me, it's pointing in the direction of
late Gershwin, not Bach!
In
Porgy and Bess there are numerous examples of the sort of symmetrical patterns you're using here. If you get a chance, have a look at the piano/vocal score of the
entire opera (not just favourite excerpts such as
Summertime). For instance, the lengthy "b" section of
Gone, Gone, Gone is built almost entirely around patterns such as you've used. (Sorry – don't have my score with me so I can't cite page numbers.)
(I have a vague inkling that Gershwin was using ideas put to him by Schillinger. Anyone have leads on this?)
As an experiment, try converting each of the R.H. chords in
Bach Study #3 into a four note "jazzy" shape: a sixth, seventh or perhaps ninth chord ... instant
Gershwin Study #1!! 