We've been excited for Griffin's Twenty ($100), a first of its kind AirPlay digital audio amplifier for AirPort Express, ever since we first saw it at the 2012 CES. The accessory is finally available, although Apple subsequently changed the portable router's latest design enough to prevent Twenty from physically connecting to it; Twenty still works with all pre-2012 AirPort Express units. A white rectangular block, it comes in particularly well-designed…
