I think maybe you're right, ubuntu 10.04 and knoppix 6.2.1 has the same kernel 2.6.32, while ubuntu 10.10 has 2.6.35 and knoppix 6.4.3 has 2.6.36 and related xorg-server-drivers.

I have read in another thread that knoppix 6.4.4 is Beta version, can you confirm this ?
Do you know when the stable version will be out?

I don't want burn a CD for a beta...

Bye.