http://www.househacker.com/ househacker/tags/flueless GelFireplaces.com carries a few really nice flueless fireplaces that are fuelled by a clean burning alcohol gel, resulting in a smoke-free fire.

From the site:

Gel Fireplaces holds three fuel cans, each container burning approximately three hours and, because there is no flue, all the heat is projected into the room. ]]> http://www.househacker.com/permanent/Alcohol-Gel-Fuelled-Flueless-Fireplaces EcoSmart produces these unique, flueless fireplaces that can be installed essentially anywhere, as they do not require any sort of permanent fixture or fitting. The company makes many different 'shells' that house the actual burner unit which operates using a green fuel. From the site:

The EcoSmart Fire is fuelled by a renewable energy source called Denatured Ethanol. Ethanol is an absolute alcohol, produced by the fermentation of sugars originating from agricultural and forestry products; mainly sugarcane, potatoes, bananas, beetroot and recently from cereals such as wheat.

What are EcoSmart Fires? The EcoSmart Fire is a new, innovative style of open fireplace. It is environmentally friendly, aesthetically appealing, efficient and cost effective. The modular design means it is versatile enough to fit into a wide range of architectural environments. Whether installed in a loft, studio, apartment, terrace house or freestanding home, the EcoSmart Fire provides the 'primal' warmth and comfort of fire while enhancing the contemporary aesthetics of today's living environments. In essence, it is designed to be an inspiring, mobile 'piece of furniture'.

And yes, according to the FAQ, the fireplaces do indeed produce heat (about 13000BTU's worth).]]> http://www.househacker.com/permanent/Beautiful-Environmentally-Friendly-Flueless-Fireplaces-by-EcoSmart Firewall Flueless' lack of a heat-liberating chimney like those found in conventional gas fireplaces. There is also an added environmental benefit in that the warm air the unit exhausts is cleaner than the air it takes in! ]]> http://www.househacker.com/permanent/Beautiful-Wall-Mountable-Flueless-Fireplace