[Batman]

One thing I've wanted to try in a game like this is to take empires with different racial techs, then gift ships to each other and refit them (i.e. Organic armor, with Psychic weapons etc)

You run into the problem of cost limits when refitting, but if you were careful it would work.

Another idea I had for a team game (borrowed from the Tycho scenario on the Gold CD) would be to make one team the "defenders" and the other team the "attackers" and make the goal for the attackers to get say, 2000M people to a given planet behind the defender's line within a given # of turns.

A lot of these ideas would require specially created maps, maybe I'll try my hand at creating one.