In what should be a surprise to nobody at this point, rumors of an Amazon smartphone are once again making the rounds. This time around, however, Amazon's fabled handset is getting a boost in the way of a glasses-free 3D display according to a new report from The Wall Street Journal.

Anonymous sources have reportedly told the publication that Amazon is working on not one, but two smartphones. The high-end model will be the one to include the 3D display as well as eye tracking features that sound a lot like what shipped with Samsung's recent Galaxy S 4.

With the Amazon implementation, users would be able to navigate content simply by moving their eyes. What's more, the eye tracking feature could help to boost the 3D effects, we're told. This would work by determining where exactly on the screen a user is looking. From there, the 3D effect would be refocused in that area.

As we've seen with other 3D implementations and eye tracking software, a lot of it is little more than a gimmick - marketing material that can be slapped on a product spec list. Whether or not Amazon can nail these features and make them truly useful remains to be seen.

These are just a few of the "prototype" devices that Amazon is working on. Other notables include an audio streaming device similar to an iPod that would work with the cloud and a set-top box. The latter seems to make the most sense given Amazon's recent streaming media ambitions.

We are told that some of these devices could be ready within the coming months while others might not ever reach production.