Let's not re-invent that wheel, shall we? Once installed to HD, knoppix/kanotix/mepis/morphix/whatnot _is_ a debian system, which arguably has the best package management of all linux distros. Painless dist-upgrades are more likely with kanotix (or mepis) which is purely sid-based, whereas knoppix mixes several debian levels and is bound to more conflicts. I personally never do massive blind updates, but just glance through the changelogs of newer knoppix releases to see what's worth apt-getting. Never forget the golden rule: no need to fix a system that works!