I want to share my experience of the denied expedite request.
Sent the I-765 (OPT) + expedite request letter + supporting documents (wife's pregnant / need insurance) on July 10th to Vermont Service Center via Fedex.
Called in to check after 72 hours. No records of expedite request. Still could manage to get a receipt number on July 13th.
July 18th. Faxed the request letter to VSC. Also the international student advisor of my school sent an email requesting the expedite processing.
July 19th. Received a fax denying my request, stating that "while my case seems serious, it is not an emergency situation." The student advisor also received a denial email on that same day.
So, try fax, you will get a response pretty quickly, at least from VSC.