This another iteration of the fireplace mantel surround that I posted in the previous blog post.  This mantel surround has the same wooden corbels supporting the mantel shelf with the large crown molding.  The big difference is the wrap-around trim has been replaced instead with simple un-fluted pilasters (though they certainly could be fluted). The ornamentation, however, should be kept to a minimum if your intention is a "Mission" style.  The drawing was created with Google Sketchup, a free 3-D drawing platform. There are no dimensions given. The width, height and clearances would have to be specific to your fireplace.