Great idea, but I don't know that I'd just limit it to Photoshop. I'd like to see a book that addressed the scope of digital portraits and illustration, and included not only aspects like postwork in Photoshop (and other digital paint programs), but also creating the scene in such programs as Bryce, Vue, etc. I agree, most of the Poser-related books seem to be technically-oriented, with little relative concentration on creating strong final illustrations (and apologies to Shamms Mortier, but the illustrations in his books would make me not buy Poser!), so anything you do should have the very highest standards for the final results.