An 8 TB NAS from Western Digital

Profiting from it's exclusive 2 TB hard drives, Western Digital announced a NAS containing 4 of these, capable of storing 8 TB of data.

It is possible to configure the disks in a RAID 0, 1, or 5.
It has Gigabit Ethernet and 3 USB ports.
It is even compatible with Mac OS X and will cost 1500€ ($1800).
Note that Western Digital has chosen to keep its 2 TB drives exclusive for some weeks and it is still impossible to buy a bare drive from retail channels.