Thanks to all those who replied.  The survey convinced the publisher that there was indeed sufficient interest, so we'll keep plugging away on the book.  We're having to do a little restructuring due to some logistic issues on the back end, but we hope to have the book finished by December, to print by January, and on shelves by JavaOne.  Of course, those are "just deadlines" and things like this tend to slip, but we're going to give it our best shot.  Thanks again to all who replied.  Check back here and on Manning's site as the day approaches for updates.