[9fans] custom-built plan9 iso?

[Corey]

Quite a while back, I recall someone was inquiring whether there was any
documentation/notes available with regards to the process of creating one's
own customized plan 9 iso - or related documentation detailing how the
official iso/distro is built.  If I remember correctly, there were a couple
responses that provided links to these docs... but I'm unable to find the
thread in question. Anyone know where I could find such info?