What a FANTASTIC idea! The ultimate paper doll. This one would be pretty easy to make too - and could be adapted for any type of costume and for either boy or girl outfits! (Imagine a cowboy with paper doll stetson . or a favourite doll outfit even!
This is a cool idea but would cost more to make than to just buy wings unless you already have the stuff. Fire Pixie Fashion: Cellophane Tinkerbell Wings Tutorial - (perfect for Halloween, Fairy Party or just for a play costume)