The market economics part is interesting to me. I touched on it in the Q&A at the end of the talk. Initially I wanted to have ships trading to make up for deficiencies in their homeworlds (agriculture, raw materials), which would also help generate revenue, and lead to conflict. However it's not so simple (hey! let's build a functioning commodities market and HFT/algo trading system). The seed of this idea came from Traveller[1]. It's worth checking out the trade system in the first edition of that game.
The original planet sim was much more complex (along the lines of World3 [2]) and explored finite resources, overpopulation, technology growth and a whole lot more, but again, for the talk that would have been overkill. I think it's worth exploring this angle as it would provide a whole different dynamic, and would be great to see at huge scale (1000's of systems or larger) and playing out at a slower pace.
Also from Traveller, the idea that information cannot move faster than the speed of light, so it has to move at the speed of transport, which creates great dynamics for trade, and the command & control aspect of warfare. Centralized governments are not so effective. A treaty could be signed, but fighting forces will not know until the knowledge reaches them. A war can start and end before the seat of power even knows it had started.
There are so many things that could go in to it. Basically the presentation is a simple version of what I'd like it to be, but I stripped it back to the essentials (spaceships and lasers!) to make the talk interesting.
[1] http://en.wikipedia.org/wiki/Traveller_%28role-playing_game%... [2] http://en.wikipedia.org/wiki/World3