It seems like it would be fairly straight forward to make this thin client work under LinuxMCE.....plus, you can get them fairly cheep on Ebay and other sources.
Sun Ray Software 4 09/07 runs on the following versions of the Linux operating system:
SuSE Linux Enterprise Server (SLES) 9 with Service Pack 3 (32-bit and 64-bit)
Red Hat Enterprise Linux Advanced Server (RHEL AS) 4 Update 3 (32-bit and 64-bit)
Minimum Supported Configuration
A server based on UltraSPARC or x86 processors (2 or more CPUs recommended)
Disk Space: 95 MB for installation; 50-100 MB per-user swap space
Memory: 20-50 MB per user depending on applications
At least one Ethernet interface installed on the Sun Ray server
Sun Ray virtual display client http://docs.sun.com/app/docs/coll/ray1-thin-client
100 MHz microSPARC IIep System Board. Includes ATI 128 Ultra graphics.
Latest client is Sun Ray 2: http://www.sun.com/sunray/sunray2/specs.xmlhttp://docs.sun.com/source/820-0414/index.html