[Cainehill]

Urgaea or Cirlani might be good for that, particularly if you lowered the number of AIs for Urgaea. Another one that might be interesting would be the Ringworld map - perhaps not what you want though, as it almost guarantees that you'd be going against a maximum of 2 nations at any given time, and you may want more of a chaotic brawl.

Abysia, Vanheim, Jotunheim, perhaps Man, Pythium, or even Ulm (I hate that nation too), anything with one or two very solid troop types might be good for the game.