mwave.com offers the QNAP 4-Bay Serial ATA Hard Drive External Network Attached Storage Enclosure, model no. TS-419PII, for $569.99 plus free shipping. That's the lowest total price we could find by $4. It can hold four 2.5" or 3.5" SATA hard drives and supports RAID 5 disk management. It also features a Marvell 2GHz processor, 512MB of RAM, FTP server, two eSATA ports, Gigabit Ethernet, four USB ports, and more.