On a smaller scale, I run multiple PC's in house diskless with NFS root; so easy to just create copies on the server and boot into them as needed, it's almost one image per bloated app these days (server also boots PC's into Windows using iSCSI/SCST and old DOS boxes from 386 onwards with etherboot/samba). Probably a bit biased due to doing a lot of hardware hacking where virtualisation solutions take so much more effect, but got to agree NFS (from V2 through V4) just works.