On the road for a few days and I miss this ? No way!
Teaching this stuff, referring to Larry's post earlier, its virtually impossible to teach Jazz theory without referring to classical harmony - I certainly wouldnt want to get my students to feel that chords are like dead lumps of notes that 'happen' to occur like railway tracks under a melody - which is kind of how Jazz theory was introduced to me - and also how it looks on a lead sheet.
I like my students to appreciate that chords are also like slices of a multi-layered cake - and each layer is a tune! And nobody does or illustrates that better than Bach.
So as to the 10th - its a legitimate interval - and
for a while in Europe I was reading charts with 7b10 chords - (written by a theory Professor!) - for the simple reason that as many have said -its heard
as a flat 3rd - particularly if it has a natural 5th -i.e not altered.
An altered dominant is a different animal - the #9 and the #5 are also part of a maj triad which includes the root note - i.e in C7 altered - an Ab triad....
As to the Resolution issues, I would consider the "#9" as a Reciprocal Major 3rd. DOWN fron the 5th
Makes sense to me - part of the 'effect' of chords with such strong dissonances is an often inherent bi - or polytonal effect created by the juxtaposition of stacked triads. You can see this in the simplest extension of a Cmaj7 chord up to its 13th-....but your C7#9(with a natural 5th) is really an Eb triad over a C triad .. that's (for me) the flavour of that chord - the amalgam of thirds and its association with the blues.
Great thread - havent seen a meaty one like this for awhile....