Assorted comments:
- Just removing some tracks from an existing mix is unlikely to leave the best arrangement of what's left. So different versions would have to be recorded separately.
- straightforward "as performed live" recordings are much better for a convincing demo CD, so they're worth doing for that purpose anyway.
- A single CD can combine audio tracks with a computer readable part containing alternate mixes as MP3 files. That will get it all into one package. A bit more production effort, but one glass master and set of pressings.
Anahata