Ok, time for some creative design work.

I just installed this mailbox and now I need a flag for it.

http://site.comforthouse.com/yswimages/smallmailbox.jpg

My mail carrier (who says she really likes the new mailbox) said that if I
just put a clothes pin on it the lid, she'll know that there's outgoing
mail. I'd rather have something a bit nicer than a clothes pin. Over the
past few years we've changed the door handles, light fixtures, house
numbers and now the mailbox to brushed nickel/stainless steel. The mailbox
is mounted on a white wall.