Electric fireplace... on carpet?

Since your house is newer, unless you specifically purchased carpet with flame resistance, it's going to be a synthetic material like nylon or polypropylene with a really low melting point. All of the different types have a lower melting point than wood will burn at. The question you need to ask the fireplace salesman is, what temperature does the unit emit at the base? If it's enough to melt the material, put clay bricks underneath it. Clay is a natural insulator, and you can set em up in some art deco style manner. Also little sparks have a tendency of getting in carpet and I have a woodburning fireplace in the basement, it's messy; bringing in wood brings in bugs, look up your local bugs.. So make sure you plan for keeping the carpet clean and spark-free!