Comment by mverwijs

We did something similar at Optiver.

    * boot a custom live cd (a la Knoppix) over PXE
    * Live CD places node into database if it doesn't exist yet, 
    using dmidecode to find serialnumbers and such
    * Live Cd keeps querying database for instructions
    * Engineer adds a profile to the node in the database
    * Live Cd slices up disk to match the profile
    * Live Cd fetches a tarball of the base OS from an URL 
    and throws it on the metal. Runs grub setup. Reboots.

Tumblr did something like this with http://tumblr.github.io/collins/.