Awesome Loft Beds--Since you won't have a window on the one end of your upstairs, this could be a fun idea for the kids area. Not necessarily a bed, but a 'loft' on top of a 'hide-out' area---or something. The bookshelf stairs are a neat idea too.
Fun Ways to Paint your Kid's Bedroom Floors
Fun Ways to Paint your Kid's Bedroom Floors http://petitandsmall.com/fun-ways-paint-kids-bedroom-floors/