Are there NAS devices that can be chained together?

Are there economical home NAS devices that could be chained together to increase your NAS volume?

Specifically, I have a D-Link DNS-323 that has a USB printer port. It would useful to be able to chain multiple devices through the USB or even plug in an external USB that the internal OS could extend. Are there ways to do this? Is this feature available in other NAS devices?

Why not try a Drobo with DroboShare? Then add or replace hard drives as required.

Yes the Western Digital NAS boxes can do this. Just plug in an ordinary USB external disk. However I think the new disk is only available as a separate share, you can't extend the internal disks to include the external one.

USB has a notion of "host device" and "guest device". A->B. An external usb drive is B, so it can work, but you can't connect two A devices together, so you need another transport. The obvious choice is the ethernet port, but you'd still need some way of doing volume management.

Essentially, this is the role ZFS plays by adding zpools, but I think you'd be nuts to run OpenSolaris on a NAS. Hope and pray someone figures out ZFS in userspace or Solaris GPL's the code.

Get a Windows Home Server box. Besides the internal expansion, you can hook up additional drives through USB. It will seemlessly add new storage to the existing shares, so you don't have to worry what data is on which drive.