Here's what I'd do:
* Jerry, walking the streets of NYC on his way to a job, runs into all the women he wronged over the years, and each one berates him. The vengeance-minded Baboo spots him and chases him briefly with a weapon --- before Newman absent-mindedly steps between them while on his route, saving Jerry's life. Newman blackmails him for his transfer to Hawaii; Jerry grudgingly pulls some strings. He finally arrives at a comedy club to find he's been bumped -- in favor of Bania.
* George meets and woos someone just like his mother -- after all, he's been transforming into Frank Costanza for several years now. This loveless relationship is not better or worse than any of the others, so they agree to marry. The Susan Foundation springs for the envelopes.
* Elaine and Puddy break up -- again -- and Elaine decides out of desperation to give the "mimbo" Dan Cortese one more shot. This proves too much of a tempation to George, who pours out his heart to the mimbo. George and Dan run off together for a life of adventure, sandwiches, and "man-love."
* Kramer is offered a TV spinoff of the failed "Jerry" pilot. He accepts, and prepares to move to Hollywood for good. He dumps everything he ever borrowed back into Jerry's apartment.
* Jerry returns to his apartment, disoriented at how his "even Steven" life has blown up in his face. His apartment is a disaster, with appliances, food, and clothes everywhere. He starts to shudder. Kramer bursts in one last time, bags packed. "NBC offered me a spinoff of your show!" he announces to an astonished and ever-more-sickened Jerry. Kramer gives Jerry a box of Cubans as a farewell present, and breezes out of the apartment. Shaken and confused about what his life has become in just one day (exes reaming him, helping Newman, losing TV stardom to Kramer), he calls George. He gets the machine -- George singing a me-and-the-mimbo message to the tune of "Leaving On A Jet Plane."
* Frantically, Jerry calls Elaine and they meet at Monks. He's carrying a duffel bag. He proposes that they elope and move to Connecticut. Elaine turns him down flat -- "I'm not that desperate yet!"
ENDING A: Jerry pulls an uzi out of his duffel bag and blows away Elaine and dozens of other minor characters from throughout the years. A cop bursts through the door and pumps Jerry full of lead. A public service announcement about gun control scrolls over a black screen. The End. [A couple of months ago, I thought this would've been the all-time most audacious series finale of all time. The Jonesboro tragedy makes this idea probably un-doable.]
ENDING B: After Elaine's rejection, Jerry tells her that he's abandoning New York to accept a permanent gig in Vegas. Just then, Keith Hernandez walks in and recognizes them. "Jerry? I never thought I'd see you again!" They pause, gaze at each other, and then Keith suddenly grabs Jerry and kisses him. At first Jerry resists, but then he succumbs. They leave Monks arm in arm, as Elaine shouts after him, "Thanks for nothing!" The End.