I'll spend a little time trying to work XPDE into my upcoming 3.3 version of Overclockix. What I understand is that the script /etc/init.d/knoppix-autoconfig needs reworking for XPDE, and then the cheatcodes need to be altered to allow it to be selected and to be made as the default desktop (think that's in boot.img). And of course XPDE needs to be installed and maybe some settings should be pre-tweaked in /etc/skel/.xpde

Still too busy between being an admin AND a help desk tech to get on this just now. Hopefully by the end of November/beginning of December.