Why not a space-map based on our solar system. 1,000 years in the future when humans have colonised it. (assuming we survive this long!)
It could work as follows... You have the various 'inhabitable' planets or moons e.g. Earth, Mars, Io, Titan etc... of various sizes. Each has a number of territories plus 2-3 orbital space-fleets. In terms of bonuses planets/moons = continents. Territories on the planet connect to each other plus the space-fleets of that planet. In turn space-fleets connect to any other space-fleet on the map.