The Leica S-Adapter H has started shipping in small quantities in the US.
You can read one of the first reviews of the adapter at Thephoblographer:
"If you’re an S2 owner and want to expand your lens lineup, Hasselblad does make many more affordable lenses. If you plan on stopping the lenses down for your work (which many studio photographers will do) then I encourage you to save some money and spring for the Hassy lenses to obtain more than enough sharpness.
If you plan on shooting wide open often the way that many documentarians and natural light photographers want to because of how much they enjoy the look of medium format, then you’d be shooting yourself in the foot by not biting the bullet and going for the Leica lenses."