The question of how to create a cut-scene within Sauerbraten has passed me by a couple of times ..
.. then, one rather boring train-ride brought me to a possible solution.
This is even a movie-esque installment - which plays it's 15-frame sequence 9 times before closing the gui by itself.
I'd like to caution you: avoid including all the frames of your 4 ½ minute 1600x1200 movie :-P
The text is created dynamically but could equally well be a set of texts displayed for less frequent updates of the image .. in a silent-movie (including sound would be possible too, but isn't part of this example) or maybe comic-strip style.
I look forward to finally seeing those singleplayer maps that people have been holding back .. ;-)