Messaging/Mail Software

I'd like to have a Webmail Software designed for my Domain Name/Website. It should have such capabilities as address book, folder manipulation, message searching, spell checking, contacts searching, threaded message listing, IDNA, shared folders, etc. It should be full featured, fast, secure, compliant IMAP or SMTP web mail client written in PHP, compatible with PDAs, phones, text browsers, Multilevel theme system, Support for Postgresql and MySql. I fancy Roundcube and this should therefore be the Benchmark and I'm willing to share what other features or attributes I'd like to have on it.