I don't have access to that kind of material, sadly--nor would I know where to find it unfortunately.
Your note about the use of the term "Lord's" without "day" is generally accurate. We usually see kyriake "Lord's", without the additional hemera "day"; and thus in translation context is necessary to understand that "day" is implied (and is so provided in translation for clarity for the modern reader).
For example here is St. Ignatius of Antioch's Epistle to the Magnesians (9:1-2):
"If then those who lived by ancient practices came to newness of hope, no longer keeping the sabbath but living in accordance with the Lord's Day, on which our life also arose through Him and His death (which some deny); by which mystery we have come to believe and because of which we are enduring, in order that we may be found disciples of Jesus Christ our only teacher." - Ignatius Epistle to the Magnesians 9:1-2
Here is the original Greek:
"Εἰ οὖν οἱ ἐν παλαιοῖς πράγμασιν ἀναστραφέντες εἰς καινότητα ἐλπίδος ἦλθον, μηκέτι σαββατίζοντες, ἀλλὰ κατὰ κυριακὴν ζῶντες, ἐν ᾗ καὶ ἡ ζωὴ ἡμῶν ἀνέτειλεν δι᾿ αὐτοῦ καὶ τοῦ θανάτου αὐτοῦ, ὅν τινες ἀρνοῦνται, δι᾿ οὗ μυστηρίου ἐλάβομεν τὸ πιστεύειν, καὶ διὰ τοῦτο ὑπομένομεν, ἵνα εὑρεθῶμεν μαθηταὶ Ἰησοῦ Χριστοῦ τοῦ μόνου διδασκάλου ἡμῶν·"
Ignatius contrasts the Sabbath with the Kyriake[n] ("[the] Lord's"), which he says is the day on which Christ rose and gave us life.
So Ignatius is obviously talking about a day, and so translators translate this as "Lord's day" for the benefit of the reader, because translating this as "no longer keeping the sabbath but living in accordance with the Lord's, on which our life also arose..." leads the reader to ask, "the Lord's what"?. Since it's obvious from context that this term consistently indicates a day when we find it in Christian writing, it becomes clear that this is the term which early Christians called this day. And this is reflected in many languages, where the first day of the week is derived from from Kyriake or its Latin translation, such as in many different languages where the first day of the week is a form of Domingo, from Latin dominus a translation of Greek kyrie. Even modern Greek doesn't call this by the ancient name after the sun, but calls the first day of the week is Kyriaki.
For Christians the association with Christ on this day, the first day of the week, changed what Christians called that day, especially amongst themselves (see Justin Martyr's First Apology to see him use "day of the sun" when writing to Pagans).
Any suggestion that it was actually the Sabbath is entirely without support, and exists solely in the imagination of those who try desperately to re-interpret and change the meaning of Scripture and provide absolutely flimsy arguments to support it.
I haven't read every post in this thread, but I imagine that a lot of the "the Sabbath is the Lord's day" arguments basically hinge on Jesus saying that He is Lord of the Sabbath, and that the Sabbath was made for man, etc. Which, obviously, doesn't even come close to meaning that Christians called the Sabbath "the Lord's Day". But that's what the Sabbatarians want you to believe, purely because they say so.
Like most conspiracy theories (and yes, I am saying that Sabbatarianism fits within the general scope of conspiracy theory), facts that don't agree with the conspiracy theory, and which in fact contradict it, themselves simply become "evidence" of the conspiracy. For example, we have photographic images of the earth from things we've sent into space, but flat earthers tell themselves that these are all fake. Why are these photographs fake? Because it's part of the conspiracy to tell everyone the earth is a globe instead of flat.
Why don't the historical facts line up with what Sabbatarians say? Well, it must be because "history is written by the victors" and the big bad Roman Catholic Church and/or the Emperor Constantine so completely perverted "Real Christianity"--and all these sources that contradict the Sabbatarian claim are simply examples of Roman Catholic tampering or some such nonsense. And if we look at a few other things, completely out of context mind you, and then if you tilt your head, squint your eyes, and then just make something up--well then you can get the kind of pseudo-historical revisionism you see in these groups.
I want to be clear here, when I say "Sabbatarian" I'm not talking about observant Jews, nor am I talking about Christians who simply voluntarily choose to rest on Saturday. I'm talking about those who teach that Sabbath-keeping (and, very often, Torah-observance more broadly) is part of Christian faith and practice. I'm talking about a specific view that is entirely out of alignment with biblical, historic, faithful Christianity as it has been practiced for the last two thousand years.
-CryptoLutheran
