Hide away kids workspace :: cool concept. To add to the idea , paint the front with blackboard paint, or make into a magnetic board to pin pictures, could also do a glass like front to hold pics/ memento's in.
For baby room above book shelf. First and last initial would be the biggest letters. Boy- tire or steering wheel for O, wooden gun for i, bullet for top of i.. Girl- Horseshoe for U, mirror or rope for O. Assign people to bring a letter for a baby shower