My friend Nancy has this heavy dinosaur of a bookcase in her bedroom. It is made of solid wood, and has a similar dimension to the Ikea Expedit. It provides her tons of storage space, but she was sick of how dark and overpowering it was. She is in the middle of a room makeover, and I helped her tackle brightening up the big bookcase.
We decided to leave the sides and front grid in the dark walnut wood stain, and paint out the boxes with a creamy white. To do this we lightly sanded the inside of the boxes and taped off the front grid with green Frog tape (I have been dying to try it out). Next we brushed a primer on and then painted each box out with a satin enamel for durability. We peeled the green Frog tape off and I was disappointed to find that some of the paint had bled through onto the grid. It seemed to work about as well as the blue painter's tape, so I don't understand the claim that it is better, and the higher price tag. We had to use some Acetone and a rag to clean up the wood stained front grid.
Once the paint was dry we purchased two sheets of 4ft. x 8ft. foam core board from the art supply store for $20 each. We cut them to the size of the back of the bookcase using a utility knife and a straight edge. Nancy had ordered the Graham & Brown wallpaper roll and we simply laid the foam board on the ground and adhered the wallpaper using repositionable spray adhesive. It took two of us to spray, hold and smooth the wallpaper. Finally we held the lightweight, wallpapered foam board up against the back of the cabinet and gently used small tack nails to hold it in place. I'll share some before and after shots of Nancy's bedroom makeover once her new upholstered bed arrives in a few weeks.