Wall-Mounted Mailboxes
To replace your curbside mailbox with a wall-mounted mailbox, you must get your local postmaster's permission.
Choose from a variety of mailbox sizes and styles; mounted mailboxes are not required to have a PMG seal of approval.
Get a wall mailbox that can hold a normal day's mail volume, including letter-sized envelopes, postcards, and catalogs.*
Place the mailbox near the main entrance so your mail carrier can easily see it.

Just found this. Maybe the postmaster will let you do it since the mail bitch has such a problem.