Giving Google’s project ARA a run for its money, here’s Puzzlephone from Espoo, Finland. It actually looks pretty nice.
You can swap out the processor as well as the camera.
They’re currently approaching a stage where prototypes can be produced. Yes, at this stage, these are just concepts.
OS wise, they’re looking to use a Forked Android but will then look for alternatives (Sailfish?).
This hopefully might see a swift change in trends from the ever slimmer bendy phone to the upgradeable varieties.
Here’s a 3D printed demo:
Cheers Alvester for the tip!