jazz composition template?

[Rachel Willmer]

I'm trying to use Lilypond for laying out some jazz arrangements, and
wonder whether anyone solved the problems I'm coming up against.

What I'd like is a template which allows me to enter the parts once but
layout the music in 3 distinct sections:

a) the original arrangement scored in concert pitch for a few
instruments (say, tenor sax, baritone sax, trombone, bass and keyboard)

b) the same arrangement, but with the horns transposed into their keys
(tenor sax plays in Bb, baritone sax in Eb)

c) finally a separate page for each instrument with just their own part
in its key

d) and I'd like the midi file to be written only from section(a)

Before I spend days trying to write such a template, does one already
exist? The JazzCombo.ly template does a good job of providing what I
need for section (a), and I can apply the transpose rules for section
(b) but I'm struggling to work out how I can easily extract the
individual parts

Any suggestions welcome!

Rachel