A GUY IN A CLASSIC navy blazer—that blue-blood stalwart traditionally made of wool, flannel or hopsack and stitched with those gold buttons—often conjures two conservative archetypes. There's the young tyke looking spiffy in his rite-of-passage Brooks Brothers jacket at Sunday service, and there's his all-grown-up counterpart, sipping a Cape Codder at the country club. The navy blazer has become so emblematic of status, it can single-handedly carry a phony Rockefeller, or a talented Tom Ripley, over the most WASPy of thresholds.

Though...