Although details are extremely limited right now, Land Rover is in the earliest of earliest of phases in planning development for an all-new Defender. For now, the automaker is only studying what exactly would be needed for development to proceed. Meaning, they're still running the numbers and planning what exactly the new off-roader would need to achieve in terms of expectations and setting benchmarks.
What's known at this point is that a new Defender would likely feature an adaptable chassis that will fit a variety of body types such as pickups, wagons, and convertibles. Once Land Rover has figured all of this out, we'll likely be seeing a concept in early 2013 and a production model sometime in 2015.