Basically, the Penns in Virginia as they desend from the four Penn brothers or 'Virginia Penns' sort out fairly well. In my case there's some confusion with three George Penns born in the 1760's and living at the same time in Amherst County, but land information, wills, etc. now have them sorted out, at least to my satisfaction. The problems begin with the parents of the Virgina Penn brothers and continue on back. It's my guess that they stem from a 'genealogy for hire' done in the 1800's for some tobaccoist Penns in Virgina wanting to prove a line to William Penn the founder. This was many computers ago and exists somewhere in my storage as hard copy. The account (surnames of Granville, Markham, etc.) are like those I've seen from 'Our Kin' or the old 'Penn Pals' publication.
An interesting line you may not know about is a person I know out here in the Coachella Valley - John Penn Lee, who goes back through Henry Lee b. 1906, Judge John Penn Lee b. 1867, Charles Carter Lee b. 1796 (who m. Lucy Penn Taylor), to Gen. Henry (Lighthorse Harry) Lee b. 1756. Lucy Penn Taylor descends from John Penn, the signer.
I haven't worked on it yet so I don't know if these Lees are related to the Lee families associated with Penns in the 1700's.