Dear Ariel: You are looking for the surname "Hadad". It's not a biblical name ,it's an Arabic name ,in Arabic the word "iron" means" hadid" and the the man who works in iron means "hadad"(smith) ,in Arabic language there is a difference between "hh" an "h" , and we spell double "d" in this word, so the correct spelling of "hadad" in Arabic is "hhaddad" but many people write it "hadad" or "haddad" because it's easier to write and spell. In Genesis we can find the name "Hadad" from the children of Esau ,but there is no relation between Hadad here and the surname Hadad(Haddad), because the first is spelled with one d and the second is spelled as I explained, there was an Aramaic god whose name was "Hadad"!(because the ancient Hebrew and the ancient Syriac were the same language but different accents). "Hadad"(Hhaddad or Haddad) is a very common surname in Syria, Lebanon and Palestine, especially among Christians ( when Turkey was occupying Greater Syria most of the smiths were Christians so their families were called after their job),you can find this name in every Christian community. and the biggest family of Haddad is originated in the Great Christian Arab tribe of Ghassan -a one from the most noble and great Arab tribes and thegreat defenders of Christianity -there is a saint from Damascus who has the surname of Haddad!
if you want more information,feel free to contact me Jack