It's already available in german stores, so can't be long until it hits US stores. Probably just a matter of logistics and/or supply.
They just said "in july" when they announced it and july is almost over soooooo. There's that.
But one little thing: I don't want to talk you out of buying it, but the 1080Ti's when overclocked all pretty much clock and perform the same. It really just comes down to cooling. The Lightning Z is (similar to the Kingpin Editions) a card for extreme (read: LN2+) overclockers and really unnecessarily expensive for "regular" use. It's your business of course, just throwing that out there.