Mike - Belkin does a 14 foot (4.3m) 6-6 pin for 400mbps FireWire.
http://catalog.belkin.com/IWCatProdu...duct_Id=265402
You can't go that long for 800mbps.
You can't go wrong with Belkin cable - it's arguably the best quality there is. It's sheathed in a silicone that slithers and does not get all crossed up like cheap plastic cable does.
Cheers
Chris