These Brights were mentioned in Muriel Earley Sheppard's book "Cabins in the Laurel".According to that book, the family removed themselves from that area, and left no descendants.
In doing Bright genealogy in southwestern Virginia, I've found that, usually, Brights fall into either the descendants of James Bright of Maryland, who lived near the TN-VA line, or the Roanoke Brights... I would think that the Roanoke Brights are a development from the Bedford Brights.(On down into Tennessee in Greene County, there is another group of Brights who orignially hailed from Pennsylvania, and were originally Brechts).
Mayhaps if you start with the Roanoke Brights, you might be able to find some research that'll help you out.