In case your idea of a Tesla-badged Shooting Brake is something inherently sporty rather than practical and simply quick in a straight line, you could try this render on for size.
As you can see, not a lot of changes were made to the brand new Tesla Roadster in order to turn it into something with more cargo space, and perhaps a little more charisma as well.
All X-Tomi Design had to do was make the roof line a little longer and get it to curb downwards at precisely the right angle that would allow for a wagon-like rear end.
The overall design isn't too unrealistic. Tesla could have probably built the car as a Shooting Brake if they wanted to, but then it would have defeated the purpose of a "next-gen Roadster".
Still, if you want to see a real life Tesla Shooting Brake, check out this Model S P90D that's being converted into a sporty Estate in the UK. The car is expected to feature even better aerodynamics than the Model S sedan, while weighing about the same.