By now, most of the Gmail users would've enabled the tabbed inbox configuration.
For emails, I conceived of a somewhat similar (though technically and practically I must admit, it could be tougher) arrangement quite a few years (more than 6 years) back. We would all agree, Gmail team has done this job beautifully though it's 2013 :).
While we couldn't execute the email stuff back then, what we've done with daily planning for an individual is very much the same as Gmail's execution of tabbed inbox. Care to find out the soul-sharing? Order a copy of Cockpit now! 814 000 2228.

