A recent job posting from Apple may demonstrate that Apple plans to grow the iPhone OS. Per MacNN, the company is currently searching for an engineering manager to be based out of Cupertino. The person should specifically be responsible for a team handling low levels of the iPhone OS, including the “bring-up of new hardware platforms.” Candidates are therefore expected to have deep experience in areas like Unix kernels and ARM-based systems-on-chip.
The new platforms mentioned are mostly likely updated iPods, iPads and iPhones, although just the iPod and iPhone are cited, and then only tangentially. The ambiguity could in fact leave room for an unannounced platform. One possibility could be an updated Apple TV, since the device is relatively simple but potentially ready to benefit from iPad-style media playback controls. The present Apple TV hardware has not been updated in any significant fashion since May of 2007.
If you have any guesses, please let us know.