The Canon 5DS is now shipping in large quantity and remains in stock for the time being. If you pre-ordered the camera, it should be on its way to you. And, if you still want to pick one up, it looks like there is enough stock to go around. Check it out here at B&H Photo.
It looks like the Canon EOS 5DS and 5DS R will begin shipping in just over a week on June 14, 2015. B&H has listed the new shipping date subject to availability.
As with other high-demand cameras, it may take a few weeks to fill all of the pre-orders. So if you want a 5DS or 5DS R sooner rather than later, you’d better go ahead and get in the pre-order line now. Check it out here at B&H Photo.