Well, this is the first Settlers 2 map I ever created with the Xaser map editor. :)
The map is called "Quad Attack".
The map has a maximum of 4 players. Each player has his own 'corner' (which I will call islands) with all the resources required to build a decent economy and big military. Every island has an inlet with a harbor close to the head quarters. The sea however is divided in land bridges each containing a 'hub'. These hubs contain 2 places to place a harbor. You have to build a harbor on 1 side of the hub and next another on the other side of the hub before you can launch ships toward the enemy, build by shipyard placed on the hub. Every player has nearly the same amount of resources. (There might be a tiny tiny difference, but that won't affect gameplay).
The map is entirely flat (I hate elevations).
You can download this map at:
http://magical.tweakdsl.nl/Settlers2/Quad.swd
Screenshot: