Trust me, I would love to see this as well. Particularly if a few of the rumors about what we're going to see with Tau/Eldar actually come true. But I don't want to get anyones hopes up.
What I will say is the Rumor list I got this all off of was posted last january, and accurately predicted each major 40k release so far (though Necron and Grey Knights were switched in their release order, and the whole sisters of battle thing was fuzzy). So provided nothing has changed I would look to hear something around the 24th about Necron.
As far as next edition for 40k goes, I heard a (tentative) new edition after craftworld Eldar, but they were aware of previous problems with updating codex's around the same time as a new edition and were attempting to plan for it. whether it's true or not, who knows. So cross your fingers.