Not a lawyer, but as I understand it the license is a matter of copyright, and the copyright only applies to the design files. So as long as you're making that keyboard for yourself then you should be good to do anything you want with the keyboard, because it is no longer using the license at that point.
Now, what is interesting is if someone were to blatantly violate the license and start manufacturing commercial keyboards. I believe their only recourse would be to revoke their license of the design files, and then it would be copyright infringement. The thing is, I don't know how copyright law would handle any damages.
I don't know if making a physical product could be a violation of copyright, regardless of if you had a license to use the design in the first place. I could definitely imagine a company trying to enforce this, and a judge throwing it out because it should have been handled with patents.
Again, not a lawyer, just speculating on a forum.
Now, what is interesting is if someone were to blatantly violate the license and start manufacturing commercial keyboards. I believe their only recourse would be to revoke their license of the design files, and then it would be copyright infringement. The thing is, I don't know how copyright law would handle any damages.
I don't know if making a physical product could be a violation of copyright, regardless of if you had a license to use the design in the first place. I could definitely imagine a company trying to enforce this, and a judge throwing it out because it should have been handled with patents.
Again, not a lawyer, just speculating on a forum.