Can VM be written in vowelless Latin?

[farmerjohn]

Yeah... but when you're dealing with an inflected language like Latin, those endings are the whole ballgame.

If I understand correctly there are several "dialects" of Latin with intermediate variants.

Here is citation from Medieval Latin by Harrington:

3.1 Changes in Gender
3.1.1 MASCULINE AND FEMININE
In general masculine and feminine remained the same, with a few important exceptions:
feminines of the second declension became masculine; feminines of the
fourth declension were treated in various ways; in Gallia, abstract nouns ending
in -or became feminine: color, honor, dolor, timor (Bonnet 503-4).
3.1.2 MASCULINE AND NEUTER
Even during the Classical period, certain neuter nouns became masculine: balteum,
caseum, cornu, etc. In popular and Late Latin this tendency is pronounced
(e.g., Plautus, Miles Gloriosus, 2.4, guttur and dorsus, masc.; in Petronius 75.10
the masc. candelabrus is found for candelabrum; see Grandgent 145).
Almost all neuter nouns became masculine:
hunc verbum (Greg. T., H.P. 1, Pref.); hunc nefas (ibid. 2.3), etc. (see
Bonnet 3 86).
Mare, however, perhaps under the influence of terra, in general became feminine
(Grandgent 146; but cf. Cat. el mar and la mar).
3.1.3 FEMININE AND NEUTER
Neuter plurals in -a came to be considered as feminine singulars (Grandgent
146-47; Norberg 58ff.):
In Gregory of Tours, pro tantae pietatis gaudia, "for joy at such piety"
(De virtutibus Martini 3 . 1 9), according to Bonnet 351, gaudia is feminine
singular, the ancestor of It. gioia, Fr. joie.
In other cases the difference between them is plainly blurred:
res mira . . . quod ( Chron. Sal. 98.3 1 ) .
Occasionally a neuter plural accusative did duty for a feminine ablative singular:
in disponsalia Mariae interfuimus, we were present at Mary's betrothal
(Gospel of Nicodemus 2.4).

Also if I'm not mistaken JKP once mentioned a manuscript written in nominative/infinitive.