It is a snow day here, so I have some time to kill. I thought I'd take another look at the G5 switch, USB, and Firewire ports. So I did a little research. Here is what I found for the Mac Pro. I am still looking for the G5, but I don't think things will have changed much. The G5 has only one firewire, and one USB port.

This diagram I find confusing as it listed as USB but shows a Sata Cable. ???