Looking through the Houzz iPad app this weekend, I came across this

I want this. Got the wife's approval and I'm thinking about starting it this weekend (gutting the old fireplace / bookshelves and starting the electrical / structured cabling)
I was originally thinking about using 2x6's as they look like the size of the structural pieces, but now I'm thinking 1x2's to frame it out and drywall over.
Mine will be deeper as I want the components under the TV to be on the shelf and not on what looks like a separate insert.
Or do the masses think it was done with wood (real or engineered) and just painted white?