Actually, I have made VERY little progress on my Smith line. In the last 15 years, I was able to discover only one generation further back than the family had known. And we found that out pretty early in that 15-year stretch. Leonhard Schmidt b 1818 in "Baden". So not only did he have a common last name, his only "origin" identifier is also very common-- the name of a "kingdom" not a town.
But I've been VERY successful on those lines that married into the SCHMIDT/SMITH line. Of course, their names arent' common at all: Fassnacht; Betz; Jauch, Glunz, Kraps !