How can I cover my slate rock fireplace?

I have a slate rock fireplace and hearth with a small, medium wood shelf as a "mantle". I would like to make a larger mantel that covers the entire front of the fireplace and wraps around the sides a bit and would REALLY like to somehow cover the slate rock area above where the new mantle will go. Ideally, I'd like to make it look like the rest of the wall, even if I have to make it much further out. Any ideas or suggestions on ow to do this? Or why I might not be able to? Alternative ideas? I want to make sure to consider fire safety, of course.