More than 70 job listings appear at the website for Amazon's hardware division, Lab 126. The New York Times's Bits blog says it has sources "with direct knowledge of the company’s plans" who say that these positions are open in part because the company is planning to finally design and produce new kinds of hardware.
According to one of the sources, Amazon has always planned on this for Lab 126; it just started with the Kindle e-reader. Believe it or not, the source says that Amazon once considered designing its own mobile phone to compete with Google's Android and Apple's iPhone, but that decision-makers decided it was "out of Amazon’s reach" at the time. That said, the company is still open to it at some point in the future.
Music players were named as a specific example of what Lab 126 might produce as it staffs up. That makes sense since Amazon sells albums and songs online. It also sells TV shows and movies digitally, so a video player seems a likely candidate as well.