There aren't any named manufacturers, and it's not clear just how far along those talks are. With that said, it's no secret that Amazon wants a better mobile footprint than it has today. Right now, you typically have to sideload some Amazon services (most notably the Appstore) due to the company's aversion to some of Google Play's rules. This would provide an end run around that giant obstacle. You wouldn't have to lift a finger to use a wide range of Amazon's offerings, and you might not have to give up Google services (as you do on Fire tablets) in the process.
Whether or not this would work is another story. The Fire phone failed in part because it was focused more on selling Amazon services than actually helping users -- if any future tie-in is too obvious, it might turn people off. Remember the dismal failure that was the Facebook-centric HTC First? As much as Amazon might like to dominate your next phone, it might have to accept a more limited presence to make some inroads.
[Image credit: AP Photo/Ted S. Warren]