There is the Knoppix remaster

There are Custom versions.

And don't forget Projects

Also a customization script. There has been mention that this script is in violation of some yet-to-be-enacted software patenting law in Europe. I dunno.

If nothing else try the
Mailing list. You can ask Klaus and the other developers themselves questions. There are a number of people who have already made customized distros. It can be done.