Hi Luka - The machine is looking "severe" as my German friend would say!
Looking very robust. Are the cars flanged? Its unclear how you are going to bolt them to the parts? Also modern machines are usually three point mounted. Then a couple (or more) of stabiliser feet. This makes it easier to level. I think the bed should be thicker to keep to the rest of the proportions.... Keep at it, Peter
afterthought - Looking at your model I see that the Z will be quite a big cantilever and will be the weak link in the design. What about making the table go up and down for the Z? Will be extremely stiff. And make it a separate part which will make casting lighter.... ??