You may already be familiar with this book, but other Loudon County researchers may not be: Brenda E. Stevenson "Life in Black and White: Family and Community in the Slave South" (New York: Oxford University Press, 1996). This 400-page book is based on research in archival resources related to Loudon County, Virginia. As the title suggests, it is concerned with family structure and gender relationships, the dynamics of patriarchy and racial slavery in the free and slave communities, marriage, parenting and divorce. The book is split into two roughly equal-sized parts: "Marriage, Family, and the Loudon White Community" and "Black Life, Family, and Community." Two chapters are devoted to FPOC families.
There are two appendices that provide gemealogically-useful information: Appendix A (11 pages), "Location of Slaves and their Family Members Belonging to George Washington, 1799", and Appendix B (2 pages), "Slave Families, Unattached Adults, Adolescents, and Children Belonging to Colonel Claiborne Gooch of Richmond, Virginia."
There are copious endnotes (good leads for sources) and a good index, but, unfortunately, no bibliography.
The book is available in paperback.