This pratically already exists, while you're in game:
alt+tab into browser
change outfit and save
alt+tab back into game
Reset
|I'm in the forums, stealing your piggies|
lolwut
*Minimizes game*
*Looks at wardrobe*
*Opens game again*
Huzzah! You just looked at your stupid wardrobe while playing a game. IT'S SO SIMPLEEEEEEEE