Small update: DVD version seems to work just fine, no synaptic initial problems.
To check it quickly with Qemu using KVM, check that qemu-kvm is installed, and start qemu (1.1.0) with
Code:
sudo qemu -machine accel=kvm KNOPPIX_V7.0.3DVD-2012-06-25-EN.iso -hdb /dev/sdb -m 1024 -boot d &
This is also a great way to check modified versions, e.g. will
Code:
sudo qemu -machine accel=kvm -hdb /dev/sdb -m 1024 &
boot and run a KNOPPIX install on /dev/sdb1 - cloop or squashfs. The hang during squashfs boot can be avoided by issuing <CR>s.

With kvm, Qemu can be a good alternative to VMware for several kinds of use. VM-based remastering may also be done there, but I'm not sure about its eventual merits. And this is of course written in 7.0.3DVD running under Qemu 1.1.0.