It's hard to imagine a current name-brand designer using their skills to contribute to the wars in Iraq or Afghanistan, but during the more morally-clear World War II, Charles and Ray Eames lent their design skills to the war effort. Behold their bent-plywood leg splint from 1942, produced for the United States Navy by the Evans Products Company, Molded Plywood Division:
During World War II, the U.S. Navy called upon Charles and Ray Eames to create a lightweight, inexpensive leg splint. The resulting design is a highly sculptural yet functional device that could be mass-produced and, being modular, conveniently and inexpensively transported. Access to military technology and manufacturing facilities allowed the Eameses to perfect their technique for molding plywood, which they had been working on for several years. In its three-dimensional, biomorphic form, the leg splint suggests the Eames' subsequent, highly influential plywood furniture designs.
Today they are collectible items more likely to be seen hanging on a wall rather than helping an injured serviceman. The Eames Gallery website sells them for $650 a pop.
Sources: Eames Gallery, Heilbrunn Timeline of Art History, do you know Clarence blog