"Blood on the snow" contains very compelling articles about how to build a one-shot session and how to use DramaSystem to fleshout background around important NPCs from any other game.
It gives a great way to switch between the heroic PCs's view and the dramatic NPCs's view.
Did you try to use DramaSystem to play such side stories in your non-DramaSystem campaign ? What was the effect on the following (non-DramaSystem) game sessions after that ?
(I'd love to hear some report about a 13th Age campaign that used a single DramaSystem game session to flesh out their Icons in a significant event.)