Try LTSP and their are many liveCDs, howtos and clients to make it work fairly painlessly.
I think the main "leap of technology" here is the use of multiple
video cards and keyboards with a single computer. That is a large
step above simple serial terminals or remote sessions. While the idea
certainly isn't new, the methodology and the features are much more
advanced. For most office work a 500MHz machine is fine. Once the
general overhead of the OS is accounted for each user only takes up a
fraction of the CPU power for their application and the I/O involved.
By using independent video cards they can take more load off the CPU
by not needing to compress and send display info for a remote session,
which would also clog the network with multiple users having
simultaneous access.
I like their idea, but I think it's something that could be added in
to Linux fairly easily with PCI video cards and USB devices. Once you
work out a frame work of assigning particular groups of I/O to each
other, start an X session for that group and off they go...
Jon.