So, later I bought a new GPU: Gainward Geforce GTX 750 silentFX. But that GPU is a lot bigger than my previous. So I need a new case
I decided to put between those mac minis I have now a wooden middle part, made from oak.
My parts are here:

In one mini case comes the GPU:

On top of that comes the wooden block with another mini, that holds Motherboard and all the other stuff:
I need this orientation of MB and GPU, because of short PCIexpress cable. It has to be really short.
Here is the MB without mac mini cases:
Dont worry. I keep you updated this time
