You know you have been looking for these.  Recapture that era when suicide door Continentals wandered the streets like herd of buffalo with these hood ornament like door knob plates. These are genuine Old Stock Triangle Brass Manufacturing Company (later known as TRIMCO) Door Knob Escutcheons, perfect for your 1950s or 1960s modern house.  These are dead stock in their original packaging.  They are solid brass, with a brushed bronze finish, but you can easily have them plated to match whatever door knob you end up using with them.  They measure about 8" across and feature a hole in the center a little bigger than 2 1/8".  Schalge A-series Plymouth and Orbit knobs are still available new in this brushed bronze finish last I checked.  Schlage F-series Orbit, Plymouth and Bell knobs will also fit.  These plates will work with a 2 3/8" backset, but a 2 3/4" or 5" backset will show them off better.