fireplace cover

We are looking to cover up our fireplace opening without sheetrocking the whole brick area or using a mantle. I have heard that one way that people have done it is to nail up some plywood to completely cover the opening, put a summer cover in place and tile around the border to conceal the plywood.

Could anyone relate their experiences with this method, or does anyone have other techniques that they have seen/used to share? We would especially appreciate pictures. I have seen people tile around the summer cover before, but only to fill the gap to the mantle, so I am having a hard time visualizing it.