Making a standalone publication out of the English translation of a paper I came across two venerable and valuable papers that are not so well-known in their community of interest. One of them is a short technical report, both concern mathematical and physical matters, for what matters. The publications are some 60-year old, and the authors have possibly passed away. These articles are written in no lingua franca. I would be quite inclined to translate them into English and revive their relevance. 

My gratification would be to provide as accurate a translation as possible, so I don't intendedly aim to add anything of my own. Yet, I would like to have these translations published so that the documents are clearly recognisable (a DOI would be nice) and widely accessible. I would also want that my effort is acknowledged, for personal recognition and as a validated item in my track record: a footnote would do.

Were this original research, the natural destination would have been a paper in a scientific journal. But it clearly isn't.

I have probed the publisher of one of these articles, who have showed the least interest in making any room for a translation, even at zero cost.

I am struggling figuring out a way to achieve these aims. Is there any institution or virtual place hosting/publishing these kind of intellectual products? Any other ideas?
If the copyright has not expired yet (varies by country but generally around 70-100 years after the death of the author), then it is illegal for you to publish a translation without prior authorization. You need to find out who the copyright holder is and ask for permission.

The journal may have acquired rights to publish a translation, otherwise you may need to find their child(ren, and figure out which of them would legally be the copyright holder now) to get authorization. It's likely to be an intractable problem.