I think Land Rover are going to struggle replacing the defender and keeping their current defender customers. The reason it's being stopped is because of new European safety and emmisions restrictions, so building a simple, reliable, robust 4x4 along with strict emissions limits just don't go together.
The brand has moved on though and they make more money out of selling toff roaders nowadays so I wouldn't be surprised if they just can it all together, or go for an "urban" off roader such as the DC100