Yeah, definitely nerdy.
Does the author mention anything about Guido's hand, Gregorian Chant runes, etc.?
Some of the very early attempts at polyphony/harmony/counterpoint from the extant music of the 11th and 12th centuries are rather "interesting" (one cannot necessarily say "good"): for example, works by Leoninus and Perotinus.
FWIW, when composing, I still sometimes prefer modes over the new-fangled things like major/minor tuning systems <smile>.
As for alternate scales, while not scale related, I am thinking of some Middle Eastern folk music that had a very complex meter of 23/8 with very specific groupings of 2 and 3.