For those looking for Edward and Margaret Jane Rainey Clanton's children, Bradley County, Arkansas is the best place to start. There are tons of Clanton's buried in the cemeteries there, beginning sometime after 1880.
To find more on Edward's parents, Thomas William and Johannah Elizabeth Johnson Clanton, Choctaw County, MS, is the best place, which is the resting place of James Clanton and his wife Leah. (Have heard nothing of them being in Arkansas, but who knows?)

Of how long the family was in Choctaw is something not quite clear to me, but it spans 20 years that I know of, beginning in 1850 and supposedly ending before 1880 (James dies in 1870, the last census record that I know of before Bradley County), since several of Edawrd's children where born in Arkansas.

If anyone needs help with this branch of the family: http://www.rootsweb.com/~arbradle/ is the best place to find relatives and where they are buried in Bradley.
http://www.rootsweb.com/~mschocta/ would be for those wanting to find out more in MS on Eadward and his parents.
In South Carolina, these couties may be possibilities on finding Ephraim Lindsay Clanton and others: Kershaw, Lancaster or Spartanburg.

http://www.familyhistory101.com/states.html is a recent find that has several states information on where to ask or find family history, although some state pages haven't been finsished yet.

Anyone looking into the Barfield wing of the Clanton family in Arkansas, I wouldn't mind helping them with what I know.