The details and current status of data requests submitted through the Data Request Help Desk page can be seen here.
Zip Code + 4
A master list of all zip codes within the United States (at the national level, but delimitated by state) as well as all outlying countries and territories. Ideally, this CVS or Excel file can be used for research purposes. (The USPS has a master list, but they charge $950 to access the data.)
U.S. Census Bureau open data lead has been notified of user request.