What a great little bit of ingenuity!
Narrow enough to work in even the smallest room, this cool little shelf includes a storage area to boot. This can be easily built using 1×12 solid wood glued and nailed together to form a long box shape. Then cover the back with a strip of thin plywood which will keep the box strong and the angles square. It also gives you a solid material to use in attaching the whole thing to the wall.
Important! – The amount of weight a shelf like this can hold is determined by a few factors. Be sure to make design choices based on your strength requirements.