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
100 MHz microSPARC IIep System Board. Includes ATI 128 Ultra graphics.
Latest client is Sun Ray 2: newbielink:http://www.sun.com/sunray/sunray2/specs.xml [nonactive]