This is a space I am going to post to over the coming year as I find this a very exciting area of interior design that is accesible to many parent. It's fun to get your childs bedroom just so and they will love you even more for it.
Here are some related good reads and ideas on the subject.
From Kids space stuff is this article - http://www.kidspacestuff.com/blog/2011/12/kids-room-cubbyhole-beds/