Folks,
Just to put the cat amongst the pigeons, I can nominate at least one major and well known airline that does, in fact, have approval to operate Cat. D aircraft to Cat. C PANS/OPS criteria in selected cases ---- with the obvious restriction being that Cat. C speeds must be flown.
I know this to be the case, because I worked for them for years, and have flown the procedures more times than I care to remember, sometimes twice a day.