So there's an enclosure that has oxford 934dsp and it has two fw 800 ports on it. I also have an OWC Voyager that has the same chipset and it doesn't pass thru any bus power and this is something that has to be powered by an ac adapter. OWC support told me that this is because of the 934dsp chipset and I'm skeptical of this claim. I suspect that there are enclosures out there than can pass thru bus power over firewire 800 regardless of chipset used.