[LAU] choir effect

[Renato]

Hi, I'm interested in how to create a "choir" effect - given a single
instrument playing (I'm personally interested in single drum shots from
hydrogen and guitar lines, i.e. not chords), I'd like to have n
copies of the signal (where n would probably be something between 2 and
20), each with a slightly different delay, volume, eq, pitch. 

Is this doable in a sane way, at least in part, with the free tools we
have? I think it should be doable in sc or pd, but I was wondering if
it's possible with ladspa, lv2 and dssi, and maybe a host like ams or
ingen.

cheers,
renato