Hi Stephen,
I have a similar need (or idea), and the closest match in the Wiki is "Run Microsoft Windows, copy Knoppix to HD & make it bootable with bootfloppy"
That is, with minimal change to a Windows PC, be able to boot Knoppix, but have HDD performance.
But I don't like needing a boot floppy.
So why not make the Knoppix CD able to do the original boot - which just means changing the search order in the linuxrc script, to look at the hard drives before the cdrom?
Even better, add some script to check that the /knoppix/knoppix file found on the HDD is the same size and date (and same checksum on first few blocks?) as the one on the boot CDROM - and only boot from the hard disk if it matches.
The result: the installation cdrom is also the boot device, and the hard drive acts as a cache for the cloop knoppix file.
Thoughts?