They might try to parody the final episodes of other great shows. Start with Seinfeld and everybody end up in jail, only to have Kyle declare "this ending sucks dick, let's get out of here, guys." Then they go into a new bunch of scenes ending in a diner, where suddenly the screen goes black as "Don't Stop Believing" is playing. Kyle again points out how shit that is and they leave the diner.
In the end, Kenny should live and remove his hood to give an epic closing monolouge with the accent of a British academic, Cartman should learn that he's Jewish, Kyle should accidentally win the war in the Middle East for Palestine, and Stan should give birth to a black baby with Windy Testaberger.