If I may suggest; have an configurable distance from colonies that qualifies as a border, and a separate distance from bases that do the same thing, write up a simple algorithm for allowing borders to merge if the distance between then is small, or split the difference when overlap occurs. Any civilian ship from a nuetral or friendly empire crossing a border should pay a small tariff to the owner, including, perhaps, customs fees. This would open up many diplomacy options, such as allowing certain ships to enter one's territory without penalty, lowering customs for some races/goods, as well as empire wide polices, such as having your patrols fire on nuetral civilian ships. Crossing borders with any military units, or building anything in another borders, should be treated as an act of war. I would even suggest taking this a step further, enabling the placement of 'claims' on systems or lesser stellar contructs, that your friends could be expected to respect, and others might be indifferent to; something like a half-border. And on the other end, perhaps even some empire rules for how far from your territory different types of ships will stray or wht type of missions outside of your borders your advisors advise. Just my two cents, and what I think of when I think of borders in space. There is nothing in a 4x space game I hate more than having a number of systems under my control, and somewhere near the middle of my established colonies a 'friend' colonizes a system I didn't. It doesn't matter that I had not colonized it yet, it is in my middle of my turf and is an intrusion, the AI doesn't, cannot, see it that way.
Edit - I just realized this si a necro post... sorry.
< Message edited by Stormy Fairweather -- 10/17/2011 10:16:32 PM >