Hello! I'm a gentoo user looking to have a portable knoppix (or derivative) installation. I already have a persitant home and all that, but what I've really been wondering is this:

Would it be possible to modify the boot such that changes could be made directly to the cd or dvd image? (say, if it was installed on a cdrw or dvdrw.)

Mostly why I want to do this is because I have a USB key that I was successful in getting Knoppix to boot entirely off of, but the image is still mounted as read-only. I realize that, if possible, having a writable image would probably take immense system power (either real time compression, or more likely, a sync-filesystem...thing), but what about a smaller image, like DSL?

Or am I barking up the wrong tree?