M.Ted, after further reflection I've decided that what you were expounding would be better called improvisation theory than counterpoint theory. Your were saying that an underlay of certain chord progressions in a C-major context encourages improvisation of G-mixolydian or D-dorian melodies over them. Am I understanding you right ?

Peter T., do you have any melodies in mind that you want to classify or accompany ?

Was my example in ABC notation any help ?

T.