[@Cale Tucker] A quarter of the galaxy is still several orders of magnitudes more then you will ever need for this game. At absolute most you [b]might[/b] need a thousand systems if this thing gets super popular and you get hoards of players.

Chances are good that the game will die before you need more than a hundred systems. If you do in fact run out of space and you don't want people fighting over land you can just say that recent advances in FTL have opened up a new star cluster and add another map.

Most of the games I played had maps and it's always better to follow the K.I.S.S. principle.