Building a stage-4 and extracting it to the local hard disc, or creating a bootable disc/stick is basically the same...

Only the destination differs.

[Edit - 2: must be talking to meself]

I'm trying to build my own cluster..I don't have like "about 30 odd computers", more like 03...but generally, it's the same principle.

Now here's an idea, create a general live-cd (or dvd usb-stick/hdd/...) on your main (quickest) computer...
(see links ...

A few questions...How is your cluster physically interconnected? By switches, routers (locally but fast) ? Or direct to the internet ?
Perhaps some computers can be booted through LAN? Diskless install using PXE boot

Do you require 64bit software, or could everything be 32bit?

[Edit]
Just found ...