Hi, I'm trying to do the same thing, but use it as a hallway kiosk, and hopefully run some of our visualizations. We bought a Samsung 460TSN-2. It has a pitiful 4GB hard drive and 768MB of RAM. The hard drive comes partitioned in half. We used Easeus Partition Master (free) to remove the D: partition and expand C: to the full 4GB (and we're still testing to see if that was a bad idea or not)

Ours has already been mounted, so I can't check the back at this moment, but it would be nice to know if the hard drive and RAM can be upgraded (does anyone here know?).
As for XP Embedded, I had to turn off the software that protects the drive from changes, enable the Windows Update service in the registry, and also change the registry entry that makes Administrator auto-login, but other than that, it's been acting normally.