We had a small CNC mill (Boxford?) where I used to work and the column had two linear rails rather than dovetails. It worked fine so fabricating modest size machine tools from readily available components shouldn’t be too difficult.
I’ve actually seen the banned video before. I didn’t actually know it had links to suppliers until this thread as they don’t appear automatically on my iPad, you have to click on the arrow to display them which isn’t something I normally do.