I have wondered if it would be possible to use demo playback to accomplish something like this. You know... send 'fake' demo data to the client in playback mode, as if the demo commands are coming from a realtime source, instead of a file? It'd be a little bit like a dummy server feeding packets to it, but since we already know so much about demofiles, would take a lot less time to develop (if it's possible at all).
Are you asking if it's possible to play the game through and or using demo files?
By sending the demofile/s live, realtime commands?
Highly unlikely, if not entirely impossible.