A well-written, knowledgeable article. Recommended!But the article lacks a pic!

6th c BC sounds like a plausible claim for a first, though the Amarna portraits of Nefertiti and other notables, not to mention ancient Sumerians, would take priority if we don't insist the deceased's skull must be found, too.

My favorite Etruscan portrait I just discovered last week on Florida State University web page, "Etruscan Art" (posted "for study only," due to copyright restrictions?), well worth a visit.
Despite its plainly unflattering likeness (unlike my own handsome features), I like the scowly old geezer atop his cinerary urn so much I'm tempted to adopt him, warts and all, as my avatar.