As reported earlier, today Sigma officially announced the pricing of their new L-mount lenses. Pre-orders are now open at Adorama and B&H.
In the US the Panasonic S1 is scheduled to start shipping on April 4th: see the listings at Adorama and B&H. The Lumix S lenses are also expected on April 4th: Adorama | B&H | Park Cameras | WEX.
Additional pictures of the new Sigma prime mirrorless Art lenses for the L-mount: