Further to the story regarding the imminent update to the iPhone hardware, it appears the handset's battery is indeed due for an upgrade. A big one - enough to cause current peripherals to be discontinued.
An upgraded battery is something most iPhone users are crying out for, but hasn't been specifically mentioned in any rumors. iPhone Otaku has been looking around the internet, however, and a large number of solar chargers for the current iPhone 3G and iPod Touch are being discontinued - with some even saying they're being pulled in "preparation for the launch of a new iPhone in June/July this year".
This can only mean they're not up to the task of charging the iPhone hardware upgrade's far meatier battery.