I'm pretty proud of the culmination of several weeks of work that I have been doing at Safedesk. Currently on a Debian system, one can install the live-package package and run "make-live iso" to generate a Knoppix-like Live CD with your own custom software selection.
I have added support for booting the live environment from a Samba share. One runs "make-live net" and a chroot environment is configured. After configuring a dhcp3 server, tftp server and Samba, one can boot any computer with 128 MB of RAM directly in to the live environment -- it all runs off the server in read-only mode. Changes are lost just like when running a Live CD.
See here if you want to know more: Debian Live Mailing List Archives
I will be posting links to that mailing list of direct downloads of the experimental Debian packages shortly. My earlier attachments didn't show up in the archives.
The company that I work for, Safedesk, will be subsequently distributing "finished" configurations: tarballs of the chroot environment. One will be an "open source edition" with no installer or management tools and the other will be an "enterprise edition" with the afore-mentioned tools and also the ability to run Windows 98, 2000 or XP inside of a virtualizer on the thin clients. The installer and management tools are written in C# and run on the Mono runtime environment. The virtualizer can be QEMU 0.8.1 or VMware Player 1.0. They can be configured to run full-screen so that end users have no idea that they are running Windows on Linux on a thin client.