Some of the higher end DV cameras can do it. My JVC when plugged into the expansion module will encode incoming video and send it via Firewire.

It would be much cheaper to buy a normal PCI TV capture card than to get one of the video->Firewire capture devices. If you want an external box then you can buy USB ones. I've got a WinTV PVR USB which works okay. You can tell it's been compressed if you look closely but apart from that it's fine. Don't get the normal WinTV USB however.

No idea what this will do to the quality of the image however. You'll be reencoding the image so it will definately degrade slightly.

- Trevor