i used to remember the old planets map how there was planets everywhere.
but since V21 has eliminated this feature, how about some planet bricks?
just simply an oval brick at the size of a 64x64 cube (or bigger/smaller), but you can only enter half of the brick (as the planets surface).
build inside it, of course.
it could have different patterns like a planet with craters or one like earth
if you are concerned about poly count, it could just be a cube or whatever.
if you are lost and have no idea what on earth im talking about, heres a diagram.