Maybe it'd be possible to do firewire if you could do what the VLab cards do for video, compress the data on the card then decompress it once it's gone through the slow Amiga busses, PPC might be up to the task of handling something like that, but I'm not sure if anyone's gonna do somethign that hard for a market losing its' most valued customers (hard core amiga nuts with cash, IE those who owns A1s/Pegs

)
The Draco had a firewire card for its DraCo Bus