Philip Pullman has at last announced The Book of Dust, which turns out to be a full trilogy running alongside His Dark Materials - volume 1 will be published on October 19th. A very welcome surprise.
More details from The Guardian and NPR.
This news is quite timely for me, as I've just embarked on a re-reading of His Dark Materials (including the little companion books Once Upon A Time In The North and Lyra's Oxford for the first time). I loved the trilogy as a youngster, reading them as they came out.