Is Firewire 800 really up to the job for uncompressed 8- or 10-bit SD video?

G-Tech makes this claim (http://www.g-technology.com/Products/G-RAID2.cfm) (2 streams via FW800) and CalDigit does as well (http://www.CalDigit.com/FireWireVR.asp) (3 streams via FW800).

Is that marketing hype, or the real deal? For now, I could live with a limit of 2 or 3 streams of uncompressed 8-bit SD.

Sure, it is. 800 Mbs is 100MBs which is plenty of throughput for SD. Check the calculations yourself at; http://www.matisse.net/bitcalc/ A firewire RAID configuration is needed (like the two you mentioned). Just be sure not to daisy chain too many devices or mix FW800 & FW400 on the same cable/buss.

yes it will work, I do it all the time