This is the mantle I built for my Dad's fireplace.  There were two primary factors behind it's design.

First was the shape of the fireplace standing out from the corner.  The mantle is really two mantles with but one pillaster in each corner. 

Then there was the finish--Dad wanted white enamel and Kay wanted oak.  As you can see, both ideas were incorporated with the white enamel finish and oak trim.

The mantle was then built in sections at my house.  Once completed, the sections were then transported to my Dad's house and assembled. 

In the assembly, the pillasters were fastened in the corners first.  A 2x4 was mounted on each side of the brick, then the top was mounted.  The lower sections were then applied in layers.