I've had some success installing on 2003 server but It still needs the DVD. I'm still working on getting the installer to work completely from my hard drive so I can install WHS through RIS. My goal is to be able install WHS on a Dell PowerVault 715N.
I have documented in Part 2 of my guide how to perform a manual installation of WHS, how to use nLite on it, and how to generate new installation media. I believe it might help you reach your goals faster. http://nliteos.com/oemguide2.html and the forum topic is in my signature.