For video editing, RAID 0 + 1. So you'd have spanning for speed and mirroring for redundancy.
Do you know what sustained data transfer rate your footage requires? You might be able to go without any RAID setup at all depending on the data rate you need for what and how you edit.
You maybe able to just go with a RAID 5; however, it's important to remember that a RAID 5 only protects against drive failure. It offers no protection against the occasional file corruption nor accidental deletion of a file.
Unfortunately, Thunderbolt ports are only available integrated into the motherboard. But, again, depending on your data rate requirements, USB3 or eSATA could certainly work.
As far as the products that you listed:
Drobo - While I've never lost any data on my two Drobos, I've also never been more nervous about the data on a drive partly due to the lack of a power switch not the early models and the Drobo Dashboard software not always working as expected.
G-tech gSpeed - Hard to go wrong with G-tech. I'd consider purchasing two: one for primary storage and one for back-up. Configure each as RAID0 for speed and use cloning software to duplicate the data on the primary drive to the backup drive on a regular basis (nightly is ideal).
QNAP TS-853 - NAS storage is not the right type of product for video editing. SAN storage is.
LaCie 4Big Quadra - I'd consider purchasing two: one for primary storage and one for back-up. Configure each as RAID0 for speed and use cloning software to duplicate the data on the primary drive to the backup drive on a regular basis (nightly is ideal).
Here is another RAID article that Harm generated.in his Tweakers Pages
That article is somewhat dated in that it was written before the latest generation of M.2 interfaces (PCIe Gen3 x4 versus SATA III) were available. Today with a single device like the M.2 Samsung 950 Pro drive there is no need for RAID for performance if your per-project workflow can be handled in 500GB of space, and there are simple workarounds if you need more space.. My x99 workstation has no RAID. You might want RAID for redundancy but I handle that otherwise. ,Here is the performance of a Samsung 950 Pro on my x99 workstation:
Easily 10 times faster than hard disk drives and 3-4 times faster than good SATA III SSD's. Now sometimes synthetic benchmarks are not what you obtain in real applications, but our Premiere Pro Benchmark on the Disk I/O test you actually get 1500 MB/second write speed when exporting a disk intensive file from the Adobe Premiere Pro timeline.