The single word name does make it difficult because the word can't be used again. There are actually more single name Stout winners than I originally thought...
1950 HESPERUS (Sass 1940)
1952 POTENTATE (Nesmith 1943)
1953 REVOLUTE (Sass 1944)
1954 DAUNTLESS (Stout 1935)
1956 NARANJA (Wheeler 1947)
1961 PLAYBOY (Wheeler 1954)
1963 MULTNOMAH (Kraus 1954)
1966 CARTWHEELS (Fay 1956)
1971 RENEE (Dill 1962)
1972 HORTENSIA (Branch 1964)
1983 SABIE (MacMillan 1974)
2009 SKINWALKER (Roberts-N., 1997)