Correct me if I'm wrong, but didn't the 600 come with a 44-pin IDE connector, the kind for 2.5" drives? If so then yes Shatterhand, you can get a 44-pin data cable and connect it to a 2.5" HD. The reason for it having 44-pins instead of the standard 40-pins is that the cable provides power to the HD instead of a separate cable like on standard HD's.
As for the floppy drive, couldn't a regular PC floppy work? Of course the 600 would ignore the High Density part of the drive. You would also want to use only Double Density disks as well.