I don't know where you live, Rev. Ward, but Larry Brandon has collected almost every document there could possibly be about the Brandons and bound them as addenda to his research, donating them to the Virginia-North Carolina Piedmont Genealogical Society collection at the Danville, VA public library:
http://www.vancpgs.org/contents/index.php
One road trip = years of research at your fingertips! Incredibly generous.
I took a research trip for the Brandon DNA group to Halifax County where I went to a farmers' market and bought fruit from Brandon Farm - a black family farm. Larry hosted me and during our conversations I asked him about black Brandon descendants. At least at that point in time (and maybe without your specific research skills) he had found no paper evidence of blood ties, just the adoption of the Brandon surname.
I was contacted by another researcher into these families not long ago on Ancestry, so a probable cousin is on the case as well!
Sally Brandon