Would be awesome if we could get some sort of mail box system in place. Could add it as a craftable item using Carpentry and maybe a check for high level cartography, I mean after all it is a world wide mail system. Heck maybe even make a new Mail man type npc that has to be killed for some of the mats required to craft it.
I agree, mailboxes for items would be cool to be able to place outside or at the front doors of houses so that when players are offline or away other players can leave them message, items etc.
Anyways, I've attached an image of the mailbox - we have yet to decide on how to distribute them but they are working