Start game, abandon homeworld.

Those are too easy. I was thinking more along the lines of a "suicide by cop" scenario, where you provoke another civilization into attacking you, giving them invasion tech if they don't already have it.

Well, if you set up the senario to begin with: Tiny map, War of the Gods senario, drengin opponents, take over another planet, build transports there, sell the other planet and the transports to the Drengin after placing them outside your capital and make taxes 100% to discourage breeding.

Or, as an influence loss: Same senario, Krynn opponents, spend several turns churning out constructors to build Influence starbases and sell them off.