Would this be enough for 4 units (with "riser" cables or adapters for the moonlanders to fit, of course)

http://www.silverstonetek.com/product.php?pid=491&area=en

I also thought on getting this one:

http://www.silverstonetek.com/product.php?pid=405&area=en

And plugging a 5V 10A transformer to it - since it is USB 3.0, anyone knows if it would handle the amperage correctly to each port?