...indeed, thought by some to be Evil.

This explains my comment about the "three B's"...[eg]

First; a question: What notes are in a Gsus4 chord?

= G, C, D, (F)

Depends on the song / arrangement you are playing. The (F) may or may not be appropriate to the implied key center, it may contradict or overpower the melody note (or erroneously anticipate it). In rock it'd be difference between, say, Journey and AC/DC. In Jazz, the 7th in this case is *available cuz there ain't no rules, and nobody seems to care much. In Folk, it is just as written (three notes). In other traditional styles, well that's not traditional notation.

EDIT : tsuwm - You'll like this one. I did a search for 37 note tunings ...and found one!

http://www.seriouscomposer.com/Tunings.htm

I can't stop laughing...