[Note: Parris is GRRM's SO and official Mud Clerk.]
And no one is more pleased with this announcement than George and myself. There will be an formal announcement posted to his web site Monday, and as he said at the reading, as soon as the publishers have firm pub dates, he'll let you know.
I've read many drafts of the book, and given the complexity of the greter story he is creating for us, this is not only a good solution to the problems of manufacturing such a huge book, it gives us complete arcs for several characters sooner, rather than telling half the story of more characters over a longer period of time. There's enough blood and treachery and gorgeous writing in FEAST to satisfy us for a good long read, I promise.
I hope most readers are happy about this, in the longer view of the strength of the series. I have been saying for several years that ASoI&F would be at least 7 books long. Check with me again in a year and we'll see if that's changed.