I've also located a John Harber in Mason and Bracken County who says in the 1880 census that his father was born in Virginia. He's about the same age as Luke Harber, he could possibly be a sibling. Thomas I believe is still viable as a close relative as well. Peter Thomas Harber was a son of Luke Harber. As in most families there is a lot of name recycling so I could see Luke giving his son the middle name of Thomas if it was a family name.