Do it yourself
As I did get myself a lot of "free stuff" from the internet I want to give something back.
UPDATE 6 February 2021: first version of all documentation published.
At Github (https://github.com/demoor-orrery/DMO) all, now available, documentation you need is published. It is not a detailed construction manual because it is to complex for that, but if you have some experience in woodworking, programming and electronics you should succeed.
Do not be afraid to make mistakes, think ahead and just start. I'm available for questions and advice. You also can visit me first if you are curious and want to find out if this is something for you.