Option to set distance between layers.

Maybe it a stupid request, I don’t know actually how layers works/rendered but this is my problem:
I’m about to make the parallax scrolling background for my space game but a significant distance clearly visible between layers and the whole thing looks weird.
I have uploaded an example here (Linux only), sorry about the size, though I don’t use them but it contains all the images, I was too lazy to set up a new project…
drive.google.com/file/d/0B1sXiY … sp=sharing

Anyway. As you can see in my example, if you move the ship on the edge of the stars you can clearly see significant distance between the actual layers. If you move in to the stars, it looks pretty good as long you don’t get to the edge, but normally I would not use that many stars I don’t want the space to be so crowded but when I use only few objects/layer it look really sh*t on the edge as you can see distance between the layer of the objects. Also, the next layer used under the layer of the ship always looks like it right under the ship no matter if it 3rd, 2nd, 4th, if it the next layer used under ship, it always seems like it right under the ship which is also something I don’t like, if you move the ship in to the stars, you can see this is well,

So basically, I wish if we could set actual distance (Z order) of layers from each other to be able to control if we want something to be in the far distant in the background or close, right under/above something else. To do this, we could set a layer distance only from the above layer, the layer on the top would be reference layer. For example, let say we have 4 layers. And we want layer 2 to be under layer 1 by 2 and to be above layer 3 by 1 and layer 4 to be right under layer 3 and after all layer 4 to be under layer 1 by 5.

[layer 1]
1
2
[layer 2]
1
[layer 3]
[layer 4]

Any thoughts on this? Maybe a possible way around it?
Thanks.