I spotted this putty grey rubber duck at Kid-O, the cool NYC kid's store. When I researched it online, I turned up dozens of "Deluxe Rubber Ducks," including a silvery Disco Duck, a camo GI Duck, and a UK-inspired Jack Duck.
Almander Gifts reports that the manufacturer, Room Interiors, is out of the duck business, so supplies are limited to existing stock. One more reason to go to Kid-O, I guess.
Minimalist Duck (currently 11 in stock), $7.00 at Almander's Alley
Kid-O, minimalist ducks and much more