I checked and Apple thinks the GBE and DA also use the plaintalk mic. Moving the internal firewire port over to GBE the sounds like an interesting project. If I do it, it may be one of those projects where once you're done you're wondering what to use it for. Has anyone ever even used the internal firewire port?
The Gigabit Ethernet also has 2x AGP and four RAM slots and line-in.(idk the specifics of the plaintalk mic though so will not comment)The gigabit ethernet may have lost the internal firewire port but it also gained gigabit ethernet on the back.
Aside from the onboard gigabit ethernet and internal 3rd firewire port.. I think the Sawooth and the GBE are pretty identical if you exclude that not all Sawtooth models can take dual CPU cards.
Actually, it would be neat to see someone drop the firewire hardware into a GBE, it has the pads for it.