The late Cardinal Jean Danielou was known as one of the foremost authorities on the ante-Nicene fathers. His landmark study of Greek, Jewish and Latin Christianity--while being justly criticized in some respects--is well worth the read. It is from his work on Jewish Christianity that I will now quote.
Discussing the Shepherd of Hermas, Danielou points out that this early Christian work plainly identifies Michael the archangel with the LOGOS. He writes:
"A characteristic feature of the theology of _Hermas_ is to call the Word 'glorious (ENDOXOS) angel' or 'most venerable (SEMNOTATOS) angel.' He distinguishes very clearly the angel who visits him, whom he calls variously 'shepherd' and 'angel of repentance' from the supreme being, whom he also calls an angel, but who is quite different from the other since it is he who sends that other" (Danielou 119).
Danielou here hints at the fact that the LOGOS is identified with Michael in Hermas although angel, according to the late Cardinal, in this case evidently means one who bears the very substance of God. Regardless of whether Danielou is correct here, the main point I am concerned with is what he has to say about Michael.
Quoting from the Fifth Similitude of Hermas, Danielou informs us that "the holy angel and the Kyrios are placed on the same footing" (Danielou 119). This conclusion seems warranted by Similitude 5.4.4 which reads in part:
"thou who hast been strengthened by the holy one (hAGIOS) angel, and hast received from him such powers of intercession . . . wherefore dost thou not ask understanding of the Lord? (KURIOS)."
Another part of Hermas that also points to Christ as Michael is Similitudes 8.2:1-3:
"the angel of the Lord commanded crowns to be brought, made as it were of palm-branches; and he crowned the men that had given up rods which had shoots and some fruit, and sent them away into the tower. And the others also he sent into the tower, even those who had given up rods green and with shoots, but the shoots were without fruit; and he set a seal (SFRAGIS) upon them. And all they that went into the tower had the same raiment, white as snow."
See also Similitudes 9.12.
From both the eighth and ninth Similitude, Danielou views Michael as being synonymous with the LOGOS in Hermas. The relevant passages from his book are as follows:
"The designation of Christ as the seventh day may be compared to another, which comes in Hermas, in which Christ is identified with the archangel Michael" (Danielou, 123).
"The comparison of the two texts [Similitudes 78.1 and 8.3.3.] shows
that it is really the Word who is called Michael" (124).
"Paul contrasts with this [the promulgation of the OT by angels] the new Law communicated by the Word himself (Gal. 3:20; Heb. 2:3). In Hermas this function is performed by Michael. This name must therefore be regarded as a name of the Word" (124).
"The assimilation of Michael to the Word is not, however, peculiar to Hermas. It occurs in other Jewish Christian texts which show up still more clearly the unskillful christianisation of the Jewish theme" (124).
The aforementioned quotes do not mean that Danielou rejects the Trinity doctrine. My point is simply that he supplies evidence that at least some early professed Christians regarded the LOGOS as Michael the archangel.
These quotes were taken from A History of Early Christian Doctrine: The Theology of Jewish Christianity (Jean Danielou).