Apparently these were a HOT item at Quilt Market! I just got the (unhappy) word from Robert Kaufman that their first printing, due in early September, is already oversold, so they will be reprinting and they don't have an ETA for that yet.
So... if you want to get these fabrics as early as possible, you should look around now to find a place that's advertising September availability. And hope that the store you've found is not already oversold themselves!
I won't be able to get mine until the second printing, which I'm guessing will be in November. :-(