I wondered about target disk mode too but I think it's MacOS only and MacOS doesn't mount the MorphOS SFS partitions (both my machines dual boot with Tiger). I also don't have a FireWire cable to connect them with.
It works with MorphOS too. I've connected two Macs with MorphOS on both, and the target machine's SFS partitions showed up automatically on MorphOS at the other end.
One other option would be by mounting partitions over network with
NetFS Revised. It preserves Amiga/MorphOS file attributes.
