That phrase at the end does have a verb: "were".
Also, I don't think synechdoche and metonymy are forms of grammar. They're literary tricks/tools.
On second look, the dependent clause-sentence fragment you're highlighting is also something more for literary. From a grammarian viewpoint, I think that clause would be better connected to the previous sentence using a comma or semi-colon. Making it its own sentence, however, does force the clause to stand out to the reader to try affecting the reader more. But again, more of poetic/literary or even ad writing/copywriting trick. Would be interested to know if it has a name, though.
Even as an English Major I was crap at grammar, (well, grammar is mostly high school anyway) but "were" isn't actin as a verb for the whole sentence, just for the subordinate phrase, more of an adjective I guess. (I don't know if "used to be" would be a verb either in that sense, though "to be" is obviously a verb)
According to about 10 minutes of research on Wikipedia, looks like you could be referring to a linguistic phenomenon called pronoun dropping (http://en.wikipedia.org/wiki/Pro-drop_language) combined with zero copula (http://en.wikipedia.org/wiki/Zero_copula), with the pronoun being "this" and the copula being "is," making the inferred sentence "This is a piece of how things were."
So, yeah, I was wrong in my first analysis of 'were' being the verb.
Good finds.
I wonder if there's a further name for what these have in common -- I guess less "grammar" and more "rhetoric" -- by putting it at the end of the scene.
Yeah, I think rhetoric might be the right term in this case. Nice brainstorm there.
However, Wikipedia seems to term them as linguistic terminology.