Bryan O’Sullivan, Don Stewart and John Goerzen announced today that they are working together on a book for O'Reilly that covers Haskell programming. Their mission is to cover the topics that are left uncovered in Haskell texts that focus on being undergraduate textbooks. The draft outline reads like a set of diffs that a Java/Perl/Python/Ruby programmer needs to understand to solve the problems they already know in a new language. And that is a very good thing indeed.
Last week, Eric also announced that he is working on a Haskell book for the Pragmatic Programmers.
It sounds like at least two publishers think there is pent-up demand for a decent, practical Haskell book that could sell more than "30 units per month". And that is certainly a good thing.
Good luck, everyone. I can't wait to read your books. :-)