The Compaq Evo T20 is a thin-client device targetted at Windows TS or Citrix TS services.
Specifications:
Some of these units support PXE booting. If you happen to have one, it is trivial to turn it into a linux thin client - just make use of a PXE netboot environment, such as PXES or diskless.
If you don't have a PXE boot model, or you wish to run linux locally, you could try 
hacking the firmware (Note, this resource seems to have been relagated to the google cache)
It appears that the driver XOrg uses for this unit can't support a bit depth of 24bits, but it does support 16bits.
There's a large number of these available on auction sites such as www.trademe.co.nz. You can pick up a second hand unit for under $100 NZ.
Hold down P while powering up, and it starts a bootp/tftp attempt, using standard ports + 10000, which is irritating. I've had some luck using iptables -t nat to DNAT port 10067 to port 67, but it seems like I also need to SNAT port 68 back to 10068, and I haven't got that working yet. Probably have to do something for tftp too.
Interestingly, if you allow the bootp to wait, it times out after an hour and tries to tftp /tftpboot/kernel on port 10069.
2 pages link to CompaqEvoT20Notes:
