The Blankenship family of my paternal great-great grandfather Rueben Blankenship, migrated to Missouri after the civil war and homesteaded 180 acres east of Noel, MO. In all account, I was told by an elderly cousin and historian of McDonald County, MO, the name originated from the Dutch/Irish, and she also mentioned Scotland given creditability. Often name changes are common of migrate families coming to America and learning the English language, and the first time I heard the original name as you have written spoken by the cousin years ago, I laughed in response because it sound of sgt. Shultz on Hogan heroes speaking in Dutch/German accent. I hope this information was helpful and good luck in your search.