I am also curious about this. This always seems to be the case with accessories for lumia phones for some reason... they either come out on launch or are sometimes maybe coming sometime soonish... on mobilefun.com they have it listed to arrive in stock in 1-2 weeks. Perhaps in conjunction with the announcement on the 11th?
Just got one for christmas (in switzerland), it's an awesome gadget. In Germany it's available, too. You don't need denim to recieve the notifications (I have Cyan with 8.1 update 1); you can add the wireless charger in the bluetooth options and edit the Settings in the device hub.