Would you consider just blocking up the fireplace altogether? I live in a house that was built in the last 10 years, so does not have a fireplace. When we moved in there was an electric fire and fireplace there to simulate the experience, but it was of course rubbish. We removed it altogether and it has freed up a load of space in the living room to re-organise the furniture and not worry about the hearth or having things in-front of the fireplace. I would never go back to having a fireplace, real or artificial, after the experience of not having one.