I personally have found that if you search hard enough you'll find "pre-made" shelving that will fit into pretty much any area. For example, I've used IKEA shelving and then "built in" around it with moldings so it looks like built ins. Most of their shelving units are 11 inches deep and have door options, or you can buy baskets to fit from them or other sources (like Martha Stewart's cubes).

I just made a nook/banquette for my kitchen from IKEA's Expedit individual wall hanging cubes. They are 15 1/2 inches deep, and 17 inches square. They have pre-fitting doors you can buy and attach, and you could leave some open if you wanted to display nicer things. Check out their website for "bookshelves" or "shelving". It takes some investigative time online or at a store to get exactly what you want. Some items they won't ship, such as the cubes I mentioned. I had to go to the store to get them. But some of the larger shelving solutions are available for ordering and delivery online.

There are other options like closet installations that are also available and more affordable.

Good luck.