Actually, right now I'd be looking at Port Multiplication SATA enclosures. Sonnet makes one http://www.sonnettech.com/product/fusion500p.html
You can actually take advantage of SATA II speeds by using these. With their controller card for PCIe macs, you can have four of these enclosures, with 5 drives in each. You can do a RAID set in each enclosure, then do a RAID stripe across two of the enclosures. The real nice thing about these is that you only need to connect one cable from your mac to the enclosure. Here is a review of them...
http://www.barefeats.com/hard72.html
As you can see, and 8 drive array gives you MORE than enough speed to do uncompressed 10 bit RGB 4:4:4 1920x1080/60i

Jason