I have you looked at the Surry Co estate files? A David Martin left estate records in Surry Co dated 1779; James Martin left records dated 1783; and William Martin left records dated 1810. There are other Martins with records from the 1800s. There's also another Lewis Martin with records dated 1898.
Eventually all of the NC estate files will be available on FamilySearch. Unfortunately Surry Co is not online yet. The files are alphabetical, so you could rent the microfilm that contains the Martin entries through your local Family History Center. Good luck.