I'm very glad we can probably do it the other way round: Using Knoppix init, and adjoin necessary Debian packages. IMHO, Knoppix init is much better! That was also what I did to make a 64-bits version of 6.4.4. One problem, is that several of Klaus K's Knoppix packages are seemingly not available for separate install. This may be because they are named the same for different releases, but may actually have some differences? (I just wonder.) A knxbootstrap utility would have to be able to download and install all Knoppix packages.

I have successfully chrooted from 7.X into a debootstrap-based 64-bits Ubuntu running, for example, 64-bits qemu, and I think that is currently the simplest way to run pure 64-bits routinely and (mostly) version-independently on a Knoppix-based system. In this situation, I am effectively using a bare-bones version of Knoppix. So, isolating the packages involved and merge them with the debootstrap set could get us there.