Hal,
DeckLink SP has been very good for me, and I have a Huge System SCSI media vaule, but since I mostly work in 8 bit I also have a Promax FireMax 2-drive RAID which handles 8bit just fine. Actually, I now use the Promax as my primary drive and the Huge vault for backup. When I went to Tiger I had some problems with the Huge drive, so I decided to use the Promax as my primary scratch disk because it is so solid, and didn’t seem to notice the change to Tiger. Plus it just flat out performs.
BTW the Kona2 is on my list of new toys, primarily because of their uprez capabilities, but since Graeme Nattress is working on a standalone uprez app, I think I might wait a bit.
So yes, FW 800 RAIDS like a Big Disk Extreme or G-Raid are more than adequate, but some of the SATA arrays would give you more throughput and insurance against dropping frames on more complex projects, or if you want to move into HD. Promax has some great solutions.