I recently purchased the 80GB Porsche external USB 2.0 HD from Lacie. It's almost filled now. I want to purchase another one, but it will be a Firewire drive. But, I was wondering whether or not it would be possible to daisy chain 2 USB drives if I decided to buy a USB 2 drive rather then a FW drive? Can it be done if I buy some sort of USB 2.0 hub?