I am not a researcher of this line, so I can provide no specifics other than from Loudoun County records.
If you know he died in Harrison Co WV (per earliest posting,) you would need to contact the county clerk to see if there is a recording of a will in their early will books. Sometimes people think there was a will when there was only an estate settlement. You might try emailing the clerk via the web form at:http://www.harrisoncountywv.com/emailtest.aspx
If you are unsure if he lived in the county, you might want to look at the Harrison Co (then VA) Personal Property Tax Lists, which are available on microfilm through the Library of Virginia Interlibrary Loan Department. Below are the reel numbers.
Harrison Co Reel 167: 1785-1808
Harrison Co Reel 168: 1809-1818
Harrison Co Reel 169: 1819-1836
If you have questions about the above you can email me directly.