Hi Colin,
I did not find your man. There were 14 men with the surname Sheppard, spelled its varient ways. Three were from VA, but their wives were named Mary (2) and Joyce. The only William married to an Elizabeth, was born 1746 NC, served from NC and died in NC 2-8-1822. His wife's surname was Haywood.
There were 3 Flanary men. None were spelled Flanery or Flannary. They were Daniel, married to Patsy; Silas, married to Violet; and Thomas Jr. married to X. All three were from VA.
You had quite a bit of research on your William and John. By not being listed in our DAR Patriot Index, this only means that no woman to date has joined DAR using that man as her patriot ancestor. Contnued research on your part to document service could gain you membership in the SAR and the ladies of your family line into DAR.
If you should need a contact with either organization, please let me know the city and state of your residence and we'll see that someone contacts you. There are people in both groups who job is to help prospective members like yourself.
Good luck in your research.
Mary
This free lookup of the DAR Patriot Index is provided as a community service by volunteer members of the Daughters of the American Revolution.