Ran across this article and am trying to reach the designers in Belen, New Mexico, to see if I can still buy the plans. The cement-like material they used is still available. (Russian fireplaces, if this falls under that heading, don't need to be U.L. Approved and might fly for our new construction).
http://www.motherearthnews.com/Do-It-Yourself/1980-11-01/Build-Your-Own-90-Efficient-Fireplace.aspx
This is a picture of the stove from the last page of the Image Gallery. Small and streamlined.
http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=67550&seq=3
Interesting. Castable Refractory cement is available from foundry suppliers but expensive.
Cob also makes fireplaces but I don't know about approvals. Kiko Denzler made some neat ones and wrote a book on them.