A writ of mandamus "issues from a court of superior jurisdiction, and is directed . . . to an executive, administrative, or judicial officer . . . commanding the performance of a particular act therein specified, and belonging to his or their public, official, or ministerial duty, or directing the restoration of the complainant to rights or priviliges of which he has been illegally deprived."
-Black's Law Dictionary, 6th edition, 1990.
A sheriff, judge, police chief, or district attorney has no official duty to sign off on your form four. Therefore, there is no way a court of law is going to issue a writ directing the CLEO to sign something he is not obligated to sign. The CLEO would continue to refuse to sign, and the issuing court would appear stupid and powerless. So forget about obtaining a writ of mandamus in this situation, because it is not going to happen.
Like I said.... just pipe dreaming.