Interesting. How would you do desktop publishing without a real (physical) keyboard and mouse?
Or do you mean to use a combination of iPad + keyboard/mouse/trackpad?
You could do all the page layout on the iPad then move to desktop or have the copy person do the text or dock with a keyboard. Like Lightroom and Photoshop, you do a lot of the editing on the iPad but then can do finishing touches on a desktop as required. It isn't too far from sketching, scanning that sketch, then digitally painting.