You mention, “The colour tones need to be emphasised by selecting chords containing those notes. Making use of extended chords or suspended chords, rather than simple triads, can be a big part of this.” This opens up a WHOLE OTHER WORLD of searching for extended and Sus chords which will also contain the flavour note and bring more variety to your chord progressions while still maintaining that “modal feel”, very, very cool! 
I think this probably happens a lot in acoustic fingerpicked folk guitar (my main area of interest).