BeGreen said:If you can get 19.5" clear height, the Country Striker 160 might be installable. It is approved for Superior ZC fireplaces.
Otherwise, your idea of extending the hearth and putting a hearth stove may work. I'd look at the Hearthstone Homestead for starters.
What is the height from the hearth, to the top of the fireplace opening?
Height from the hearth to the top of the fireplace opening is 25 1/4".
The Homestead pictures and specs look nice. Do you have personal experience with it?
Incidentally, the depth of the hearth is 20". Would it be an option to place a stove like this on the existing hearth without modifications/additions?