I don't know anything about the history of barn quilts, but I want to share some pictures of the "barn quilts" at our Red Willow Bible Camp. The camp has become known for, among other things, the annual fundraising quilt auction. I donate quilts to that auction and have shown many of them in the pictures section here on the board.
These pictures show "barn quilts" on the camp buildings. The small one is hanging by the Phoebe cabin door. (Each of the cabins has a name.)