You can try to use the blender unit as 10[SUP]-4[/SUP]m which will pretty much let you have objects of 1 - 2 meters, while keeping detail at objects with sizes around 10[SUP]-6[/SUP]m.
But as JA12 said, it’d be better to fake it. Using such a large gap in the coordinate scale, can very easily cripple your workflow, with a complete lost of precision at the OpenGL level, Z figthing artifacts, difficulty in selecting objects, etc;