What came first - the tablet or the smartphone? Well, in the case of Apple, HTC, Samsung and numerous others - the smartphone. But it seems as if Amazon is going to mix up the mobile evolution by releasing a smartphone next year, following the launch of the Amazon Kindle Fire tablet this week.

The 7-inch tab went on sale in the States on Tuesday and there's more than a murmur that the tablet will be followed by a smartphone brethren before the Christmas lights go up in 2012.

Those murmurs are fuelled by an investor note from Citigroup’s research department which states:

"Based on our supply chain channel checks in Asia led by Kevin Chang, Citi’s Taipei-based hardware research analyst, we believe an Amazon Smartphone will be launched in 4Q12...We believe FIH is now jointly developing the phone with Amazon. However, we believe that Amazon will pay NRE (non-recurring engineering fees) to FIH but the device and multiple components will actually be manufactured by Hon Hai’s TMS business group."

FIH are Foxconn, the company that Apple employs to develop the iPhone and the iPad and TMS are reportedly the company behind the Kindle ereaders.

The Kindle Fire phone will apparently be powered by a Texas Instrument’s OMAP 4 processor, with Qualcomm's dual mode 6-series standalone baseband on board.

There's no more spec details at present, but the mention of OS royalties to Microsoft suggests Android - it's common for the software giant to pick up fees for patent rights for Google's platform. Chances are then, that we'll see a fully-Amazon flavoured OS over the top of Android.

The phone will cost between $150 to $170 to build, and we all know Amazon isn't shy in making little, or even no, money on its hardware - so we'd expect to see it hitting the shops priced below $200 if the rumours ever do ring true.

Q4 2012 is a long way away though, Amazon could well be a bit too late to the smartphone party...