I can answer that one.
And the answer is: not easily.
Theoretically, you could do it by installing one on top of the other, letting the two package databases co-exist side-by-side. In practice, you would have a devil's own time matching up versions and dependencies satisfactorily, coupled with the fact that there are key system files the two distros do differently - sometimes quite differently.
OTOH, I think Karsten did once chronicle installing a distro using chroot in some fashion in preparation for switching over to it...
Wade.
