I did set up some disk-less clients, working for Take. Doing
so, I had to find out a way to do things not possible using
the standard root-filesystem-on-nfs. Well arrived at my
home, I sat down and wrote a HOWTO
The HOWTO describes how to mount more than one filesystem before init sttarts, how to have network interface drivers as modules in an initrd together with a network root-filesystem, and how to mount any network filesystem as root.