Multisession Knoppix?

Is it possible to create a multisession version of Knoppix, similar to Puppy Linux - so the CD base Knoppix system is burnt to a DVD+-R, and the remaining space used at least for file storage, ideally also for holding updated and additional programs and settings.

I have some 8" DVD-Rs, and this would be a rather nice use for them.

I'm not sure I understand the question.
By multisession are you wanting multiple operating systems on one disk or are looking for space to store files usuable with say other OS's i.e. windows?