We did this for a client a few years ago. This portion of their house was built in the 1930's. They had a traditional wood fireplace with a tiled hearth. Ashes were always on the floor, plus it was drafty. We ditched that, raised the firebox off the floor with cinder block, and added a gas insert. We framed the new firebox with porcelain tile. Above it is a rosewood panel. The entire face sticks out a couple of inches, owing to the original construction which was not cost-effective to remove entirely. The ceiling in that spot is about 10' high, and the ceiling is vaulted, so it does not overpower the space. Maybe this will give you an idea.