I also have some Knoppix live CDs remastered over and over to encompass changes or to add modules that were developed for projects.
But now I have a bunch of USB keys, ranging from 256MB to 4GB. I Stated all this by first getting my Knoppix 5.1 on an USB drive. With the help from Pen Drive Linux article which I have provided the link below.
Get all your Linux on a USB drive, I have a Knoppix DVD image on a usb Drive. So I can do all my work even if I am totally disconnected from the net.
I also have a bootable SD drive on my notebook, I will try to get my knoppix on it!
Knoppix 5.1 Release notes on PenDriveLinux
Pendrive Linux's Knoppix ready for USB Drive