I just found my relative, John Jacob (Johann Jakob) Lenggenhager in the village of Oberhelfenschwil, St Gallen, born 1834. He came to the US in 1849 and changed his last name to Lenk. Settled in South Dakota. I did exactly what the person suggested. Got microfilm from the 8 villages that Lenggenhager originated from and methodically went through them. The book recommended that contains Swiss Surnames is a great source. I ended up buying a CD version because I'm constantly looking up names. Good luck. This isn't an easy task and glad to hear someone else is looking into the Lenggenhagers. Let me know if you find out something interesting. Could be a relative.
Kathy Nienhouse