A live demo CD version of the Sun Java Desktop System came with Linux Format's cover disc. The actual distro is based on SuSE, per the reviews, but the live demo is based on Morphix! Bizarre.

Unfortunately, the demo is as proprietary as the actual distro, so there's no freely-available download. It didn't run on either the AMD K6/166 or the K6/550 I tried. It did run on an Athlon 2600+ box. It was faster than all the other "full-size" live Linux CDs I've tried (and I've tried quite a few), but felt much more stripped down.

Nice-looking interface, but it is Gnome at bottom (I prefer KDE), and it's got some strange quirks. For example, instead of xmms, you get a media player written in Java that has severely limited capabilities.