As these are prototype devices and are hand built, it's possible that the cases are just temporary working models. This could account for the seams (unless they point to the possibility of a user replaceable battery which again goes against current Apple design philosophy). However, as far as the overall design is concerned, I believe that this is pretty much what iPhone 4 will look like. If you look at the iPad, it shares a very similar aesthetic. Both have squared, aluminum edges with cutout speaker slots. They also share the same speaker grilles. The big difference is the glass/ceramic/whatever back which is there to facilitate radio transmissions (could the new phone also have a FM radio built in?). Like many, my initial reaction was that this device looked rather ugly compared to the sleek curves of the 3GS, but I have to admit that after comparing it to my iPad, the design has sort of grown on me.