Sorry about not posting the "after" for so long! It's not a dramatic difference from the bookcase's earlier condition, but I was able to shuffle and edit our books.
There is a bit more breathing room for resale, and the wires have been tucked away. A quick fix with no cost to me.
Wait--I did break the picture light trying to screw it to the back of the painting's frame. Add another to the yard sale wish list!
Update: I found a photo of the bookcase as it looked when we bought the house. We beefed up the molding and added contrasting paint to the back of the shelves for more impact.