What about a darker harvest, with 95% cocoa powder instead of 86%?
History loves to repeat itself, despite the better attempts of us peasants. So another Dark Harvest, with a slight twist and perhaps a different ending would be interesting. Or, going back even further in the EU/AU timeline, why not pick something major that happened and tweak it to our needs, or take a planetary thing and make it happen on a galactic-wide scale. I can't think of anything right now, unless you want a horde of Yuuzhan Vong on a dealership coming in.
With that, here's what you could do: the seedship was thought lost before the Vong even entered the galaxy. A wrong turn made or something. Anyway, they've finally found their way to the galaxy, where they caught signs of their brethren's descendants living. But guess what! While these old-new Vong are still fresh in their intolerance of infidels and the likes, the other, already-been-here Vong are fairly relaxed about things now...or are they?
Meanwhile, individuals like the Sith are trying to persuade these guys to help them with galactic domination, whilst everyone else is trying to either convince the new Vong to not attack or to try and get rid of them.