Hello,
the recent thread on this topic prompted me to make a multi-instance init script: https://gist.github.com/7adietri/9122199
It's basically the current official init script and torservers.net's "instances" mechanism frankensteined together. Maybe other people will find it useful too.
Config files should be layed out as described on torservers.net: https://www.torservers.net/wiki/setup/server#multiple_tor_processes
Best regards, Alexander
tor-relays@lists.torproject.org