I assume you mean a prefabricated fireplace. The wood burning ones are likely to be deeper than gas fired ones.

The web is probably the best way to find what you are looking for. Go go Google.com or to Bing.com and type into the search box any word or phrase that likely captures the thing you are looking for. You might have to try several different words or terms. There is a trial and error process with this until you find what your need. But eventually you will access more web sites than you need or imagined in your wildest dreams existed.

You might also want to consider an alternative to a fireplace. There are manufacturers of small gas stoves that are installed directly against a wall. They are described as "zero clearance" which means that that you do not have to surround them with noncombustible material. Some of these stoves are quite attractive, but a different style from a fireplace.

There's a lot of stuff out there. Happy hunting.

BGD 34 will work for you, its very thin, thats what I got, putting in a corent, shell dept is 13.5" to put it in.

Thank you. I'll check out the Napoleaons.

We are also considering Heat and Glo Slim line.

Any progress on the thin fireplace? Although it's a unique idea, I'm a bit too traditional to go for the single flame unit. Wonder if it actually puts out any heat!

Middle of the summer, who reads "firplaces" at this time of year?