Sans Digital's more affordable TowerRAID series works great for video editing workstations. The build quality is not as good as the EliteStor line (which is really intended for mission critical server applications), but they are lighter and not too noisy. I have not used the 12G model, but I can vouch for good luck with their 6G models and Areca controller cards.
Here's a link to buy the TowerRAID TR8X12G 8-drive model for $650 direct from Sans Digital:
It's a pretty new model and Newegg does not seem to show it yet.
Areca controller ix series cards only have one external 4x cable, but you can route additional cables from the internal connections (SFF-8643) out to the external units (SFF-8644). PC-pitstop carries 8-port SFF-8644 to SFF-8643 "pci-slot" adapters too for a really clean setup, but I prefer the single cable approach - less cost and fewer connections (better for reliability).
I currently have five WD Black HDDs connected to the Areca controller in RAID 3. I just read that those drives are not recommended for such use. It seems to work okay, but with the RAID controller, I expected better. The speed tester shows 800-900 Mbs write speed (sometimes higher), but only 300-400 or so read speed. All the rest of my drives are older 6G SATA drives that I had planned to put into the new storage unit until I can afford enterprise type drives. I understand that would be the best use for my older drives for now. They are currently either sitting around or in external USB and eSATA enclosures that are too small and slow to do anything with. And it sucks to have five or six external drives connected to my computer.