I downloaded the .iso for the live CD version of the Sun Java Desktop System. When booting it reports being based on the Linux distro Morphix, version 0.4.
I was sad to see the X autoconfiguration fail on my Thinkpad a20p, so I couldn't test it on my primary system. I was able to boot the CD on my Shuttle SB52G2 and on a Dell Optiplex GX100. On the Shuttle JDS was not able to automatically detect my Linksys WMP55AG A+G Wireless PCI Adapter. I didn't feel like fiddling around with Linux so I wasn't able to access the network on the Shuttle.
Since the Dell had a recognized Ethernet NIC, I was able to manually configure it for network access. JDS (like most live CDs) tries to find an IP via DHCP, but I don't provide DHCP on my test LAN. Launching a terminal showed me I was running as user 'morph', which means Sun didn't change even the basics of this Morphix version. I was able to 'su -' without a password and configure the network myself.
If your hardware is supported, I think JDS is a fairly slick distro for the average office worker. StarOffice 7 is included. Here are screenshots. Sun is throwing lots of energy at this effort, with support forums, a blog, and an O'Reilly book.