At the Frankfurt International Book Fair for 2006, Guinness (the World Record people, not the Stout people) gave out certificates for two world records:
1. Worlds most published author - which went to L. Ron Hubbard, with 1084 works published, exceeding the record held by Brazilian author Jose Carlos Ryoki with 1,058.
2. Hubbard also received the World Record for "most translated author" with published works in 75 languages.
Here's the full text of an article about this phenomenal author: L Ron Hubbard earns two world records.
Of course, Hubbard's been dead since 1986, so the awards were presented to his publishing firm, Author Services.