Hi
I also fascinated by horn stuff and is determined to learn this as well.
(Just ordered Mojo Horn Section at
www.vir2.com). Anyway some experiments I have done included a midi fx that converted polyphonic keys down on keyboard, sending each key to a different midi channel and thereby a different instrument.
This is excellent for finding what works better together when playing chords like this.
A free midi fx midiPolyphony that does this is:
http://www.kvraudio.com/forum/viewtopic.php?t=279800 Great fun to play with.
I played around one night 3-4 years ago making a short song with some stuff from Dimension Pro if I remember right. I'll see if I can find it....
EDIT:
Blue Brass