Bed under a sloped ceiling. Instead of a headboard - curtains. (P.S. This blog post has a lot of detail about what the person did as far as decorating and picking things out. Too bad a lot of it is scavenged or found, but some things can be replicated. Lots of good ideas.)
Website full of rooms and ideas...8,335 different pics of girls/boys rooms, and playrooms.
Kinderzimmerdeko in Pastellfarben / Pastel Girl's Room