Unibody design is one of the leading expectations on iPhone 5. A puzzling feature on the so-called leaked iPhone 5 pictures is the two-tone metal backplate as featured in Cult of Mac. Don Lehman wrote a detailed article on this and provided a good explanation on the reasons behind the two-tone metal backplate. I agree that two-tone back plate (with a strip at the top and bottom of backplate) is due to antenna reception issues. Basically, the two-tone back plate is not a design choice, but it is a solution (and possibly the only good solution) to implement a unibody back plate into iPhone 5 given the requirements of several antennas.
It is clear that iPhone 5 housing in the “leaked” pictures is a major improvement in functionality providing thinner form factors. Quite possibly, the new design also provides a stronger structure than the two glass-plates of iPhone 4. However, this improvement comes with a baggage of visual clutter; that is two-tone metal backplate. Being a lifetime Apple user, I consider this a slight departure from Apple’s philosophy of simple and clutter-free design. Perhaps some may consider the two-tone back plate beautiful, but it is certainly not clean and has more visual clutter than top-notch Apple products we have been used to. Therefore, this might be a disappointment for some of us Apple fans if this is indeed the next iPhone 5.
In engineering terms, the “leaked” housing design is an amazing engineering work and is a very robust design. The iPhone 5 design is highly flexible and can incorporate various material combinations, glass-metal, plastic-metal, ceramic-metal, whether the metal part being aluminum, steel or Liquidmetal. This design also allows Apple to implement a unique product differentiation within iPhone 5. For example, an entry-level iPhone 5 (with the least GB storage) may have a plastic-aluminum combination, whereas a high-end iPhone 5 (with higher GB storage) may have a glass-steel combination in the backplate.
The beauty of iPhone 5 design will hinge upon its execution, and specifically on how the seams between different materials (e.g. metal/glass) are finished and managed. Looking at the leaked pictures, the seams were not finished and refined to the standards that I expect from Apple. It should be noted that the phone in the leaked pictures was assembled using leaked components, rather than by Apple itself. Therefore, it is still possible that the leaked iPhone 5 housing and components are indeed not for the final model, but for early working prototypes. I am hopeful that the final iPhone 5 will be much better looking than what is seen on the “leaked” pictures.
Finally, I think it is unlikely that we will see Liquidmetal in iPhone 5 this year despite numerous rumors.Certainly, the metal backplate in the so-called leaked pictures of iPhone 5 does not look like Liquidmetal to the eyes of yours truly. It is possible that we will see Liquidmetal in iPhone 5 at its mid-life update (iPhone 5 LM ???). As I mentioned above, the robust and flexible housing design makes it easier to implement new materials to the backplate.