Latinitas could be described as high quality Latin. If I want to refer to the same thing for other languages, can I use nouns like Graecitas, Anglicitas or Finnicitas? (I am not sure if Anglitas and Finnitas would be better.) This is not something that I expect to find in Latin grammars, so let me pose the question in a different way: Would such derived words be understood by a sufficient amount of today's Latinists? That is, is the point likely to get across without further explanation? Of course, the answer depends on Latin proficiency of the audience; the problem is to describe this dependence in some way.
Or, for a less amibiguously formulated question: Was this construction ever used productively by analogy to Latinus > Latinitas, in any Latin literature?