I LOVE stuff like this! I would take the shelves out and:
1) paint the entire wall (including in the shelving area) with the Lamp Post and snow scene of Narnia.
2) Paint the Unit brown and do a faux wood finish on the cabinet doors to look like the wardrobe.
3) Buy the 2" fiber board letters (available at Hobby Lobby etc) and spell out the names of the different supplies to be stored; ie: BRUSHES, PAPER, CRAYONS, PENCILS, ACRYLIC PAINT, TEMPRA PAINT etc. Paint them bright colors and then, using small wood screws, attach the letters to the shelves. They will act both as labels and bumpers for the supplies.
Lots of work but it would look cool. Let us know what you finally decide.