As a couple of helpful folks (thank you) pointed out, I
had forgotten to fill in the offsets in the disklabel.
Either they're putting something in the drinking water,
or I'm getting too old to partition one drive while
attempting to recover another one (See PATA thread :-( ).

So I changed the offsets to a more conventional layout
and newfs stopped complaining.

So in summary, if you have overlapping partitions,
*and* use a 16k/2k filesystem, newfs issues a wierd
complaint about "Read-only file system".  Seems like
newfs is wrong here, but I have more important fish to
fry, like trying to find a way to recover my data.