It's not "hard", it does take time though. If you like lego or similar, the build itself is quite enjoyable.Ok, the last pics put me off, seems out of my manufacturing league.
Aluminium is the obvious material. There are companies that will laser/water jet cut it for you to make it easier. It can be left bare, brushed, polished, or painted. Alternatively, engraved brass? Veneered plywood? Perspex?...Suggestions for final panel materials gratefully received.