When and where did you get the floppy images?  There was a critical
change (for some controllers) to wd.c that just went in recently, and
as far as I know, there haven't been any new binary sets advertised
since then.  If you have the source, you can check the version number;
if wd.c is prior to version 1.84.2.6, try a later version.

   labelling disk wd0...overwriting disk with DOS partition label (n):

	   which if you respond with `y' goes immediately to the mkfs
   stage.

	   Now, oddly enough, NetBSD has trashed the partition table,
   fips says (including the Error):

That's hardly surprising, since you told it to.

    I can mount /dev/fd0a as a msdos device and copy stuff from it (hence
   the output from fips) but disklabel says:

   disklabel: ioctl DIOCGDINFO: Invalid argument

    but disklabel (only for wd1 or wd1d -- presumably for the
   inconsistent reasons currently being discussed) says:

The latter is the `default label' created by the driver because it
couldn't read the real one.  Some kind of default label is required by
the wd (and sd) drivers to be able to talk to the disk at all.  (This
requirement could be removed, but there's no particularly good reason
to remove it.)  The floppy driver doesn't bother creating a default
label because it doesn't need it.  (In fact, the floppy driver itself
completely ignores the label; it only allows creating one for the
benefit of newfs(8).)