I realized that I forgot one thing: the case feet!

I previously cutted and painted in grey 8 wood discs:

To make a “metal” effect, I sprayed a little quantity of white paint. It was just the quantity to obtain little white dots on the grey background, so these drops seems like light reflections, as in a raw metal surface.
This is the effect:

This is the sequence:

First the grey backround:

Then the quick pass with white spray, to form the little white dots:

I glue the felt pads:

And this is the result: