Sorry to jump in so late on an 18-page thread but just my 2¢ - they said it'll come eventually but they're working on other items at the moment.
You have to remember that there are only two kinds of landable bodies: moons and planets.
If it has an atmosphere and it's a moon/planet you'll eventually be able to land on it.
BUT if you can land on one you should be able to land on all of them. Can't do that yet. Some may be barren, some may have life. How does the game engine determine which you can land on? If you can land on ALL of them, you have to then make sure ALL of them are ready for use, not just some (unless you're doing the permit locked thing and why would a planet near Beagle Point be permit locked and by whom).
This will be implemented bit-by-bit as I see it. Maybe gas giants, then some thin atmosphere words, etc. If you want ALL of them NOW, you might want to take a look at NMS.
Eventually it will happen. We all know this game is still a "Work in Progress". Be patient, young padwan.