It appears that `darcs annotate -p` does something similar to `darcs changes -v`, 
but the name is confusing.

Max Battcher has suggested revisiting the idea of `darcs show patch`.

I'm starting to think that if we just implemented the darcs plugin mechanism,
people could just install darcs show patch as a plugin rather than us
implementing it ourselves.  Guess it then boils down to what the right defaults
should be.  I think this one is a do-er decides.  Send a patch; we'll argue
about inclusion later :-)