In 1860 William Ellison was South Carolina’s largest Negro slaveowner. In Black Masters. A Free Family of Color in the Old South, authors Michael P. Johnson and James L. Roak write a sympathetic account of Ellison’s life. From Ellison’s birth as a slave to his death at 71, the authors attempt to provide justification, based on their own speculation, as to why a former slave would become a magnate slave master.
http://www.civilwarhistory.com/Black%20Slaveowners.htm
The next two were a Jewish immigrant from New York and a free black man. Can't remember which order they came in, offhand.
Interesting sidelight on Russell County history -- most of the old slave census handwritten returns from before the Civil War have not survived, as they were destroyed during Reconstruction. Somebody took a bunch of volumes of the handwritten returns and walled them up in the old death cell of the Russell County Jail when it was decommissioned. They weren't found until 60 years later when the old jail was torn down. Needless to say, they're an invaluable resource, not only for historians but for black genealogy researchers trying to find ancestors.