Interesting article (here is english translation): http://www.heise.de/ct/english/05/12/148/
They did couple years ago similar thing with Win NT 4.0 Workstation when they converted it to
NT Server. The difference was that at that time conversion was 100% success (there was no way
to detect difference between real and DIY server, all upgrades worked etc.). All they did back then
was make two small changes with hex editor and burn everything to a new disc.