Thanks for contacting me.I don't find any of the surnames you've shared with me nor do I at present have any mixed marriages to my knowledge. Well, that's not quite true as we do have an indian and white marriage on my mother's side back in the 1800's.
We all know that in genealogy things can change in a hurry but at present the closest I've come is in researching some other VA families and having found that their slaves were given free man status and lands in the early 1800's. Then the free men married white ladies and they bore mulatto children. These same men also had their own black slaves.
I am interested also in the fact that you are researching these same surnames of James, Hancock, Marable and Mason. Does that also involve they having at one time lived in Rutherford Co. TN?