One of the better full service fireplace shops in Southern California is Capo Valley Fireside in San Jaun Capistrano. They have over 30 live burning gas fireplaces and fireplace inserts. Good selection. Otherwise, most fireplace shops do not feature live burning units. In fact most stores are Patio and BBQ shops first with limited fireplace products on display.

If you aim for a serious amount of heat, you need to get a direct vent insert. These cost at least $2K. They are energy efficient in that most of the heat does not go up the chimney like the typical gas logs that look nice but do not give out real heat. And stay away from unvented systems which are a safey hazard and outlawed in many places. Do a search of direct vent on this forum to find out more.