After sharing a few items sitting on top of the bookshelf in my livingroom I thought I would share how I made the bookshelf itself.
For the shelves of the bookcase I bought two sets old bi-fold doors from my local recycle center for $5 each. I cleaned up the doors, removed the hinge and knob hardware and patched and painted over the holes left from the hardware. Alternately you could use wood boards but I opted for the cheaper route.
To support the shelves I made columns of bricks. Colorwise the concrete bricks I bought didn't exactly fit in with my living room so I used some cream spray paint to get the color I wanted. As a tip, once you stack the bricks only three faces will show so you can conserve spray painting by only painting those faces.
For stability when building the bookcase it is important to stack the bricks in pairs, alternating the direction as you stack. It's also necessary to use some L-brackets to anchor the shelves to the walls and I wouldn't build it taller than I did (about halfway up the wall).
All told, the project, not including paint drying time, took about an hour of hands on time and cost me about $35. Not too bad for a custom bookcase!