It doesn't seem to have gotten any mention on the lists, but over at LinuxMusicians FalkTX has announced a new Ubuntu10.04/KDE4 based liveCD tailored to audio production. I can't comment on the performance of it, but he has certainly put alot of effort into centralizing and streamlining things like audio system settings and plugin management (it probably has more options for plugins than any distro I've checked out, with guis for managing installation of linux and win vsts, for example.) It also has things like Ardour and ArdourVST installed in parallel.

Anyway, I'd say it's worth checking out if people are looking for alternatives:

http://kxstudio.sourceforge.net/

-michael