An email in the ABTAPL list raised a very interesting question.
In the IVP Ancient Christian Commentary on Scripture, in the volume on Hebrews, there is an excerpt from Ephraim the Syrian. Looking at the reference, we find this:
Marco Conti, trans. Commentary on the Epistle to the Hebrews. Works of Ephrem in Armenian. ACCS translation project.
Except that no publication appears to exist. According to IVP:
Marco Conti (Ph.D., University of Leeds) is professor of medieval and humanistic Latin literature at the Ateneo Salesiano and lecturer in classical mythology and religions of the Roman Empire at the Richmond University in Rome.
In 1836, the Mechitarist Fathers in Venice published the works of Ephraim from the ancient Armenian versions, in 4 volumes. Some of Ephraim’s works, indeed, no longer exist in the original Syriac, and the Armenian versions are all there is. A bibliography is here. But I have not been able to locate this Venice edition online.
However in 1895 they published a Latin translation of the commentaries on the letters of Paul. This I did find, here. And in the PDF, on p.217 of the PDF (p.200 of the printed text) there is the start of material on Hebrews!
It would be interesting to know whether Dr Conti prepared a complete translation of Ephraim’s Commentary on Hebrews. I hope to find out!