Hearth Cabinet is a company out of NYC that can custom build a unit to size for you. http://hearthcabinet.com/

I would not recommend an ethanol-fueled fireplace, like the one mentioned above, unless you have no way to get gas to it.

As a matter of fact, I would not recommend a ventless fireplace at all, unless you have no way to vent it. There are too many indoor air quality issues.

Having said that, here are a couple of gas models from a reputable company:

The White Mountain Hearth "LOFT" series vent-free: http://www.whitemountainhearth.com/wmh/index.php?view=loft-series-burners-and-fireplaces&parid=82&pagid=103&mlnid=82

The White Mountain Hearth "Boulevard" vent-free: http://www.whitemountainhearth.com/wmh/index.php?view=boulevard-linear-fireplace&parid=82&pagid=279&mlnid=82

Part of the issue is that unvented products are limited to 40,000 BTUs of gas, which sounds like a lot, until you have to spread it over a significant width. Which means a 5' wide fireplace will have a dinky flame.

There are a LOT of vented products out there: http://pinterest.com/pyrotom/places-of-fire-linear/

I believe you would be much happier with something vented, aesthetically and functionally.

Exactly what are the indoor air quality issues with the ventfree fireplace?

If you remember basic chemistry, perfect hydrocarbon combustion produces carbon dioxide (CO2), breathable oxygen (O2) and water (H2O). None of these are harmful in the amounts we're talking about, but the water produced can cause other issues.

About a gallon of water is produced per therm (natural) or gallon (propane) of gas that is burned. So a typical unvented fireplace will produce a gallon of water in about 2 1/2 to 3 hours.

A little bit of moisture in the air is nice - it keeps static electricity down, keeps your wood furniture from drying out, etc. - but lots of it can lead to excessive condensation on windows or other cool spots, mold and mildew issues and so on. The moisture will also grab whatever is in the air and stick it to the surfaces it condenses on.

The next air quality concern is related to odors. Even though the gas itself should burn without odor, anything in the room air - air fresheners, cleaning chemicals, even potpourri - will cause there to be some odor while the fireplace is burning.

Another related odor issue is associated with ceramic fiber logs. The hard, heavy ceramic refractory logs don't seem to add any to the smell, but the ceramic fiber logs have a funky smell of their own that actually can get worse with time. We don't recommend using fiber logs. Since modern fireplaces don't always have media (logs, stones), this may not be as much of a concern.

People that either have sensitive noses or respiratory problems (athsma, emphysema) shouldn't use unvented products. They will be most likely to notice problems.

Lastly, I've only been talking about when the fireplace is working properly. If, heaven forbid, the logs or other media are placed improperly or the burner is set up incorrectly, you'll have aldehydes (bad sour odor), carbon MONOxide (CO) and sooting, which can be a disaster, obviously.

We handle unvented products, but only recommend them where you can't vent, and cautiously even then.