If the membership of battle mines ever exceeds 150, the map would get pretty crowded. However, if I may suggest that at TL14 a player be allowed to build a "Dimension Gate" that would allow them them to warp to a parallel battle minia with the same rules and a distinct communications channel, senate, weather, etc.
In essence it would be new map highly separated from the first one, which players from a crowded world could warp to. Such a device would be constructed similarly to a DDD or Scrambler, but either in 20% chunks for 15 Refined, or 5% chunks of 5 Refined material. Possibly there would be a penalty of 3 tech levels and a hull so that it's not done often. (Or it takes a burst of power to activate, that's where the capacitor would come in)
That way the topology aspect of Battle Mines wouldn't be a limiting factor to number of players.