That didn't take very long, Toshiba just announced their 5TB drive and now LaCie has announced an external drive with 5TB of storage.  You will need Thunderbolt to properly interface with it, perhaps a good thing for users since transferring 5TB over USB 2.0 is not the most enjoyable experience.  This also means you can pick up the 5 bay model called 5big and have 25TB of external storage available for you.

CUPERTINO, CA – Today, LaCie announced the availability of 5TB, 7200 rpm hard–drive capacities in its 5big Thunderbolt Series, 2big Thunderbolt Series and d2 Thunderbolt Series. Delivering external storage products that range from 5TB single drive systems to 25TB RAID solutions boosts storage capacity by 20 percent. This increase showcases the company's commitment to provide the fastest, highest capacity storage solutions on the market.

Increasingly larger file formats for film and photography have driven the demand for more storage capacity. The availability of 5TB hard drives enables LaCie to deliver significantly more storage capacity in its same compact desktop designs. This saves professionals valuable desktop space.

LaCie's 5big Thunderbolt now features a capacity of up to 25TB, which makes it the largest 5–bay storage solution on the market. Combined with industry–leading speeds up to 785 MB/s*, it is the ideal product for video professionals to pair with a Thunderbolt–enabled computer, like the new Mac Pro, to drive 4K workflows. Photography professionals will appreciate the larger capacities of the d2 Thunderbolt and 2big Thunderbolt, with the same fast transfer speeds and responsive photo browsing that they depend on from these products.

The new capacities are also available on the LaCie 2big Quadra and d2 Quadra storage solutions. All products can be purchased at the LaCie Online Store and LaCie Resellers.