is there any consideration to offer a universal hub for the simucube base so that everyone could mount his own (real) racing wheel ?
You mean like wheel plate? Look at Ascher Racing offerings.
If you don’t need a button box, like @Andrew_WOT has suggested, then you can mount a wheel directly to a Simucube QR - as long as it has a 50.8mm or 70mm pattern.
I have a Momo 280mm wheel like this purely for rallying old cars like Escorts
the same way I have done it, but in future I want to have buttons and paddle shifter. Maybe I take the ascher hub if GD have not such product. I think most of the drivers would like to use there own wheels having flexibly instead of a fix one.
is it possible to get some information about attachment size and hole distance, I am thinking making my own mounting adapter for other wheels ?