I've also been working on the map, but I wasn't happy with the way it was going so I've put it on the back burner for a while. I started experimenting with GraphStream and produced some beautiful demos, but in the end I concluded that GraphStream is probably not my best option. It seems better suited to the purpose for which I think it was originally designed: non-realtime rendering of large dynamic graphs, with the ability to record screenshots and make videos for presentation.
Before I gave up on GraphStream, I used it to produce something I've never seen before: a visualization of an entire TradeWars universe. Some interesting structures are apparent, but I don't know that they're anything that wouldn't be found by SWATH's bubble finder.
When I get back to working on the map, I'm going to try Prefuse. It looks like it will be useful for a whole lot more than just the map.