My wife just got her H4 re-validated. Here are the details
Documents sent --passport, my H1B extension copy, her H4 extension copy, a letter of employment, a fedex airbill with my credit card number for payment on it. Cashiers check for $175 (single check).NO ENVELOPE was enclosed.
Date sent - 23 Nov by fedex. Date recieved by St.Loius 25 Nov
Date Visa Stamped Jan 13. Date passport recieved 14 Jan. by Fedex.
Hope this helps. By the way they returned the copies of the approval notices and the employment letter.