A fairly do it yourself idea could be to get a bunch of random depth lengths etc wood pieces and stagger them on the wall. You can integrate the shelving and it will all look cohesive. I would even add a deeper shelf at the base area about the height of the credenza with a couple of legs, maybe in metal. Paint them the dark finishnand keep the light paint behind for depth.Good Luck!

They look like they were made for cozy recliners. One for reading, the other for watching tv.

Great ideas, thanks for the thoughts. I like the unified look and we're considering it as part of a 'built in' cabinet option - I like the flexibility of the floating shelves.

The staggered wood could be awesome. How do you get started on it?

Love the free floating shelf idea by Dytecture, perhaps use the Lack shelves from IKEA, and cut them down if need be, since the ends die into the wall anyway.

The first thing to do is to get the overall dimension of each niche, width height and depth. With that you can figure out how long is the longest length, deepest depth and the quantity you will need app. If this becomes a challenge you may want to consult with your local cabinet shop. You can even buy some pieces and start to play around with the look you feel works best in your space and laying the pieces out on the floor will help you see it come together. Once you have the first couple attached to the wall secured to studs the rest should fall into place and follow suit like tiling. Good Luck!

I just looked back and realized you had some helpful dimensions. You can buy 2"x4"x8' (actually 1 3/4"x3 3/4") and rip them down in half of the depth and some 1/3 of the depth so you have variations. Cut the lengths down to halves and 3rds. The shelves that need to be deeper can be made of plywood as well. These legs in the left would look good too!