I'm not so sure that it's doing the same thing the Drobo does.

Yes, it looks like Qnap might be a little friendlier than your standard RAID, by letting you do an in-place expansion, but from everything I've read of the examples you're posted, the assumption is still that you are going to replace all the drives in your current RAID. It also assumes the usual RAID drawbacks: that all your current drives are identical and that all the future drives will be identical as well.

The idea of Drobo (at least in theory) is that, to begin with, you can just throw whatever hard drives you have in there. And when you want to expand, you can take out any single hard drive and replace it with another of any size and of any manufacturer (except Seagate ). So I could start with a 250GB, a 300GB, a 500GB, and a 1TB drive in my Drobo, and when it started to fill up, I would replace the smallest drive (the 250GB) with whatever I wanted and be done.