Hi Cousin! I happen to have an aunt who is the family historian, and has detailed records of the McKinney's of Greenup Co., KY, including several family bibles. I have a copy of her handwritten family tree, in which she mentions Sallie. I have the entire family line from 1826 (on the McKinney's) Alexander M. McKinney m. Phoebe Riffe Feb. 11, 1854, and their children, whom I believe someone else already listed for you, but then I have their spouses and children. I have ther Riffe's back to 1659 and the Hatfield's back to abt. 1600, (in case you didn't know, yes, the Hatfields of the famous Hatfield/McCoy fued, although only related, not participants, that I know of! This is in my aunts writing on the family tree, and I quote her, "My great grandmother Nancy McKinney, (no husband we know of) "received a letter from her father, Alexander M. stating that he was writing a letter for Salley. I seem to remember that name as one of her sisters, and could be a nickname for Sarah." Anyhow, I have been corresponding with her about our family, (no she isn't online). She is very meticulous, and seems to have many family bibles including the McKinney family bible.
Let me know if I can help you. Feel free to e-mail me.