I had started out looking into booting a virtual machine running Linux with the mnt-system share and directing the default file on the tftproot host to point to that IP. Glad I kept digging around.

Found that for me the best solution was install Windows Services for Unix on my Windows 2003 server. This is all that I needed to get the NFS shares. Then enabled "Let Everyone permissions apply to anonymous users". Now I can boot any of the computers to Knoppix via PXE.

Only side affect I've noticed so far is that I can't get Knoppix loaded this way to shutdown or restart, it just close and reload the GUI. For now the Reset button/power cycle will work, but I would like to be able to shut down normally.