I also appreciate the reference list, blacksimon!
But reading through much of it, I only got my impression about the noimage approach confirmed. That will use the adaptations already built into Knoppix in an optimal way, I think. And people shy of remastering, can use utu's overlay approach to minimize persistent store space. (Actually, overlays+occasional remasterings might be a very good scheme.)
My own motive for working with this now isn't so much media wear as system robustness and efficiency. Media writes is the most costly, in terms of time and resources, and least predictable kind of operation I perform running Knoppix, so having a way to control them would greatly facilitate flexibility. Like running Knoppix off the micro sd card in my mobile phone (which worked well last time I tried, but a bit too slow writes then..)