Have just heard that "Prospero Burns" has been pushed back to Jan 2011.
This is due to Dan Abnett having health problems (nothing too serious).
So, the book missed the deadline for publishing.
"A Thousand Sons" should still be out in March as this is by Graham McNeill. It's a shame about the delay but someone's health is far more important than a book, no matter how cool it's going to be!