[link|http://www.newegg.com/Product/Product.asp?Item=N82E16822144002|http://www.newegg.co...m=N82E16822144002] - not an enclosure, but it supports FireWire 800 for the MacBook Pro.
My other option is to start treating my Linux workstation as a server, and backing it up instead. I don't know what the options for fileserving to a Mac are yet, though.