I already posted a comment on the iussue in this thread before MorphZone went down and part of the database was lost. The comment went into void too, so I'll repeat the important points.

There is a FireWire stack for Amiga: it's the MacroSystems' one. FireWire devices (mass storage and digital video) are supported. The stack works on an AmigaOS 3.x system without custom chips (the DraCo), therefore porting this one should be much easier. Then you would need only the low level device (which you would need anyway). And it's supported by a couple of MacroSystems own programs for videoediting (that are much better than what we have now - nothing).
The difficult part would be to know wheter MacroSystems are availble to licence this code, considering they're not selling Amiga related products anymore, but they're still in the video editing market.
I would suggest to try this path before picking more esothic alternatives...

Kind regards,
Andrea