Fortunately, the good people at the Criterion Collection know a good deal more than most, and they recently released a collection of his historical TV films on DVD. Sadly neither of the above titles are included, but as the collection is titled Rossellini's History Films: Renaissance and Enlightenment we can but hope that there might be a future series called Rossellini's History Films: The Ancient World (or something similar) which might also include his works on Socrates and Augustine of Hippo. Actually we can do more than that. Criterion have a "contact us" page with a specific email address for sending in suggestions. To which I will shortly be turning my attention. This is actually part of Criterion's Eclipse series.
Thanks to Peter Chattaway for the link on this one. He also links to an article on this set by Dave Kehr at the New York Times.