Options for 4-bay hdd enclosure

It really depends on what kind of speed you need. Qnap do some good enclosures :

http://www.amazon.co.uk/s/?ie=UTF8&...vpone=&hvptwo=&hvqmt=b&ref=pd_sl_53djlefchu_b

I personally have Thunderbolt, and use a Pegasus R4:

http://www.amazon.co.uk/Promise-Pegasus-R4-SATA-300-Thunderbolt/dp/B005CO0446

The Promise is not a cheap solution, but it is very fast...I use it for real-time work and It eats video etc. The cheaper Amazon offerings may better suit your needs...Just add HDD's

 

Probably none that would be as cheap as a single 3TB Seagate Backup Plus Firewire 800 drive for $169.

http://www.amazon.com/Seagate-FireWire-Desktop-External-STCB3000100/dp/B00829TIEK/ref=pd_cp_e_2

 

i just finished setting up one of these today, very impressed so far considering the price i paid.

MediaSonic RAID box