I have seen occasional discussions over the years about this, but I don't know of any pirate transmissions that have used these. The biggest impediment, I would think, is the lack of pirate DXers who have equipment to hear these modes. There's not much point in buying or building equipment that can transmit in this manner if no one will be listening.
The same has applied to FM pirate broadcasts on the HF bands, although every once in a while someone will give that a try, most likely using ham equipment that supports FM. Usually they will get a small number of reports, probably from DXers with ham equipment that can receive FM, or from those who know tricks allowing FM reception on AM or SSB receivers.