How likely is it that Apple will launch an iPhone 5 with a "radically" different design? Well, not very likely we reckon, based on the fact that the iPhone 4 was itself very different from the previous iPhone 3GS, which itself was very similar to the iPhone 3G and first generation iPhone.
PCWorld's Jeff Bertolucci reckons that Apple will stick to the "if it ain't broke, don't change it" mantra, something that's not necessarily what Apple has done in the past (the iPod springs to mind).
There are a number of reasons why Apple might consider resisting any "radical" structure change. There are already tens of millions of accessories out there with which the current iPhone will need to be compatible, from casings to alarm clocks and docking stations.
This means for example that Apple will stick to the proprietary connector that came with the various iPod, iPad and iPhone devices that came before it, with all the electronics and necessary volumetric space that it requires.
It will also be a logistical nightmare to change the machinery necessary to produce the casing, the motherboard, the display etc.
Retooling costs money - a lot of money, and at a time when Apple apparently wants its partners to cut their prices, this wouldn't be a welcome move.