Ask HN: Scriptable IMAP/SMTP servers?

I'm looking to build a mail system that can be accessed via normal IMAP/SMTP clients (mobile devices, Apple Mail/Thunderbird/Outlook, etc.) but with a decent scripting ability. The goal is to have inbound and outbound emails to be reviewed by a third party before they're delivered. Googling has revealed a number of dead tries at making a Node IMAP server, a long-dead Lua-scriptable IMAP server, but nothing particularly usable.