We have painted Bible verses along the ceilings of all our preschool classrooms - this photo is of our nursery. Maybe something about creation or even use your Chronicles of Narnia theme for a verse or inspirational saying. Here's an example of one we painted in our nursery. You could also organize your storage of extra supplies in colorful crates or those fabric collapsible boxes to minimize the cluttered appearance and bring more color to the space. Be sure to label so you know what's in them! Also if it's also an AV room, we have found cute pictures, canvas art and items like film canisters and reels to decorate the tops of our AV room shelves. I'll try to remember to take a picture to show you how we "staged" those shelves.
Oh, and WHAT A BLESSING to have that storage!!! Wow!