If you've noticed I've been silent, its because I've been busy updating the BIRT book to cover 2.3.x, 2.5.x, and now 2.6. Due to page number constraints, we had to cut two chapters from the book. But their loss is your gain. Those two chapters have now been released, free of charge, to the public thanks to my publisher. These chapters cover how to build stylesheets, templates, libraries in one article, and building a Bugzilla reporting site in the other (unrelated to my jobs BIRT demo site, BIRT4Bugz).
Check out the articles here: