* Translation - should be possible by having a lang="" attribute on
the <doc> element but I'm not sure this is desirable.  Perhaps using
some kind of ...

* Include mechanism - toyed with the idea of using an include
mechanism to pull in the docs from an external file.

* Does this make sense for D-Bus - maybe?  Wasn't a specific goal but
might be useful.

* Can we turn this into a mechanism for getting documentation on
services automatically:
  % dbus-man Hal.Manager