Unfortunately ZFS depends on the Solaris fault management daemon (fmd) to handle failing disks by itself, something FreeBSD doesn't yet have a replacement for.
Thecus 7700 supports ZFS. 7 drive bays though.
I am looking for something like this instead of tape backups. I looked at some NAS devices that hold five drives and seem pretty robust. One of the devices can mirror itself to another NAS over the network so you can have two separate places to store your data and not have a hardware failure of one device kill the other.(one exception would be the case where the master device gets degraded to the point where bad data is being written to it and then propagates the changes to the other device. I don't know how likely this failure situation is though.)
I think the dual NAS idea is a good one; I'm considering it.
I do crave a higher bandwidth connection to disk.
I wish OS X would ship with ZFS. A mac mini + zfs + JBOD seems fascinating.
I've used ZFS + Solaris at home and with Sun hardware in several companies for 'appliance' servers that we deployed on-site in remote locations. We were able to achieve reliable storage on a 1U server without paying for a RAID card. It was great. ZFS is great for the budget. Now I want it at home.
But where's the simple appliance to do this? For a home fileserver I just want a small box large enough to hold 4 disks, and I want it to set me up a RAID-Z or mirrored ZFS when I pop them in, and serve them via all the common methods I pick via a simple web interface.
Why has nobody done this? I've looked, and the only ZFS 'storage appliances' are software packages.
At present I have a RAID-1 mirror on cheap external drives on a mac mini, and I KNOW the array will degrade within a couple years. Has always happened to me with software RAID. ZFS would be great, but there is no such appliance. (And yes, I tried the patch to make OS X write to ZFS... so slow it virtually locked the system).
Please, someone: build this. It will be a great product. You can offer much better storage reliability than can cheap RAID with ZFS.