Drobo - doesn't sound uncool, that thing. Data redundancy at array level when using heterogeneous disk configurations, that's already nice. Classic arrays often have the problem that only equal disk sizes are used (larger disks then have unused free space), which is why increasing the capacity forces you to replace all disks. Something like the Drobo is of course much more flexible, and behind the Time Capsule it would also be a quite practical device. And the price is not really shockingly high - considering what you get for it.