First, the black on black color scheme is going to have great appeal to the style conscious tacti-cool crowd. I suspect future pics of member's guns are going to include glimpses of the new Winchester rounds.
The duplex load concept is not new, George Washington encouraged his troops to load their revolutionary muskets with buck and ball. During the Seminole Wars (1815-45), buck and ball loads were a standard issue and continued through the Civil War. Winchester's Supreme Elite PDX1 shot-shells are a another twist, with contemporary packaging, on a historically proven concept and will probably become a popular HD load.
The .410-bore version of the PDX1 seems obviously aimed at Federals .410 handgun loads. You do have a Taurus Judge, don't you?
When will they be available?… a good question. The handgun ammo is available, but I've not seen any of the shot-shells. I'm guessing Winchester's first obligation is to filling government contracts.