This is what i would like to happen. I could stand one full more movie just to let my plans come through.
Team Cullen/Pack/RandomVamps are having the regular court talky talk thing, and then they say something that pisses the Volturi off. So they start fighting and everything.
The cullens are actually winning using Bella The Speshul Snowflake's shield powers. Right as there are only Jane, and the three main Volturi left, the sky is opened up and Forks Washington actually is sunny (holy sh!t, rite?) and so everybody is sparklin it up. So everybody is looking up and they see Nyan Cat floating down on a marshmallow from Heaven.
At the same time, the ground starts shaking. Before they can be saved by Good Nyan Cat, Tac Nyan comes and pulls them into Hell below. So Edward and the other vamps are like chilling and introducing Bella to all the other vampy friends in Hell, when suddenly sh!t starts happening.
So then they get thrown out of hell because they aren't bad enough and all they do is sparkle. Hell is like reserved for bad a** test cheaters and stuff. So they're back in the gay meadow. When suddenly this Unicorn stampede starts running around like they're on crack, and they're closing in on the vamps.
So they vamps are all like "Oh ya unicorn blood bet that tastes good" and so Edward grabs a unicorn and like drinks it's blood. He's like drinking the streams of rainbow goodness and stuff when suddenly HE starts turning all rainbow colored the more he drinks. So he like spits it out but he can't do anything about being a rainbow so they need help because he can't be sparkly AND a rainbow or else no vamps will take him seriously. Even though he isn't taken seriously anyway, he wants to change this.
So Speshul Snowflake, *****, Sparklepire Edward, and the Mini Sparklepire Snowflake all go to find a special place where they can drain him of his Rainbow blood.
So they get that taken care of and then they come back down to Forks and then they look into the meadow and suddenly they see Buffy The Vampire Slayer, Blade, Dracula, and a whole bunch of other bad a** vamps and vamp hunters. The Cullens and the Pack and the Volturi and all the other vamps die. The End.