I've taken screenshots of some of the recently revealed updates this past day of Brawl (pictures included) 
Character Selection Screens
Selection Screen has a white background until you confirm your characters. Then it becomes black. Notice the nice white colored Mario (Fire Mario anyone?)
The confirmed players. Notice the black background and a dark scheme for Meta Knight. He also comes in white and devilish red. Sadly no Black or White Yoshi....
Stage select screen also has a white background. This is a demo after all, so these may or not be changed. I personally like the crayon effect the stage preview images have on the left side.
Victory Screen. White background again with a touch of pink. In the video, Meta Knight indeed has a remix version of Kirby's Victory song (as Masa stated he would months ago in his Toukouken)
Victory ranks and points.
Items
Advance Wars Assist trophy (knocks opponents off stage)
Little Mac Assist Trophy
Metroid Assist Trophy (clings to opponents)
Power Drill Assist Trophy
Warp star
Spikeyball (Sea Urchin)
Fan
Blue Beam Sword
Mr. Saturn
Homerun Bat
Star Rod
Fire Flower
Lips stick
Partyball
Capsules
Motion Sensor bomb
Gardevour Pokeball
Heart Container
Maxim tomato
Food
Smartbomb
Extras
Characters have 3 Taunts~
Peach's FS puts players to sleep/numbs them on the ground and drops peaches around the stage.
Sonic's Super Sonic FS allows him to fly freely around the stage similar to the Sonic 3 Doomsday Zone
Character Selection Screens
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Selection Screen has a white background until you confirm your characters. Then it becomes black. Notice the nice white colored Mario (Fire Mario anyone?)

The confirmed players. Notice the black background and a dark scheme for Meta Knight. He also comes in white and devilish red. Sadly no Black or White Yoshi....

Stage select screen also has a white background. This is a demo after all, so these may or not be changed. I personally like the crayon effect the stage preview images have on the left side.

Victory Screen. White background again with a touch of pink. In the video, Meta Knight indeed has a remix version of Kirby's Victory song (as Masa stated he would months ago in his Toukouken)

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Victory ranks and points.
Items
Advance Wars Assist trophy (knocks opponents off stage)
Little Mac Assist Trophy
Metroid Assist Trophy (clings to opponents)
Power Drill Assist Trophy
Warp star
Spikeyball (Sea Urchin)
Fan
Blue Beam Sword
Mr. Saturn
Homerun Bat
Star Rod
Fire Flower
Lips stick
Partyball
Capsules
Motion Sensor bomb
Gardevour Pokeball
Heart Container
Maxim tomato
Food
Smartbomb
Extras
Characters have 3 Taunts~
Peach's FS puts players to sleep/numbs them on the ground and drops peaches around the stage.
Sonic's Super Sonic FS allows him to fly freely around the stage similar to the Sonic 3 Doomsday Zone