I would also be interested, too, if you have found any information from this request. John McCombs and Mary Ann Busby were most definitely my 6th or 7th great grandparents. I have been unable to take the McCombs tree any further, but Mary Ann Busby's tree goes back to the early 1600s in Baintree, MA.
However, I have a theory that the McCombs line might have been in either New York or Pennsylvania prior to 1820s. My father always heard a legend that the family was in one of these two states before Ohio. I also have a theory that we might be somehow related to President Martin Van Buren, who was from New York. Almost every boy in the family had "Van Buren" somehow worked into his name. For example, there were sons named "Van Buren McCombs," "Johnson Van Buren McCombs," "Martin Van Buren McCombs," and "John Van Buren McCombs." There are at least a dozen Van Burens. (I'm surprised that Van Buren isn't my middle name. LOL)