Check http://www.ecosmartfire.com/en/home for indoor or outdoor flue-less fireplaces that burn on non-polluting de-natured alcohol, efficiently heat a room, qualify for an energy-saving tax credit of up to $1,500.00, are U.L. approved, come in a many designs and can be used on no-burn days.
Besides being portable (although some models can be built-in so they look and operate just like a traditional fireplace), another benefit with this fireplace is safety over gas fireplace. The risk of a gas leak is eliminated!
Cost savings is another plus. In new construction there is no need to construct a flue or run a gas line.
There are both complete fireplaces already designed and 'Burner Kits' for use in custom-designed fireplaces - many dramatic designs are possible. There are also 'Grate Ranges' for inserting into an existing fireplace.