Andrew,
I don't know of a utility that will read HFS disks in the floppy or hard
drives, though AmiCDROM is a freely distributable CDROM driver that will read
Mac HFS CDROMs. I know this sounds a bit off the track, but you might try
downloading it and seeing if you can ask the author about using it, or a
modified one, for reading from floppy. The author can be reached over the
Internet, I think.
-larry