Special update: GameTrailers has the Nintendo World 2006 trailer for Super Smash Bros. Brawl.
Snake fits right in, amusingly enough. And look, a Mario Kart stage! Looks like some old stages come back, and some changes for others; Mario Kart looks like a revised F-Zero stage from Melee, with the karts racing at the screen, and the first stage they show has the same layout as Melee‘s Battlefield.
Fun stuff all around.