ATA-over-Ethernet
Storage requirements seem to be growing quickly after hosting remote backups. I have been searching for a newer RAID appliance using ethernet. It is referred to as ATA-over-Ethernet. From a high level, it performs similar to a software-RAID. Since this is a block device, it should behave no differently but allow you to stash it away into a closet. Their driver covers all the platforms.
My concern was the overhead of a network protocol, but they claim theirs only contains basic read/write. Stuffed directly into the ethernet frames. Other protocols such as iSCSI and Fibre Channel exist, but they are at a much higher price point. Essentially, all you have to purchase is a rackmount frame full of drives. From there, you have the flexibility for any RAID variety, using the file system you choose.