On the forums you can see how to make one-- I used this system while waiting for shipment of the REAL one. When it arrived, I switched immediately to this unit. The only negative is that there are no instructions on how to install. It is reasonably intuitive, but better to search the ReadyNAS forums to see pictures and videos-- it requires a simple screwdriver only.
Note, the power supply in the ReadyNas is one of THE weakest links due to small size, heat, dust, difficulty with air flow, etc. Also the factory struggles to get a quality supplier and is constantly changing the design. ALWAYS have a spare. This will work with all NV and NV+ models, but not pro or other models.