You started
this thread a few months ago and got several recommendations. None of them panned out?
Also, your lack of search result may be due to your search terminology. Safari typically denotes watching game, which isn't typically of Moroccan Sahara jaunts. And while Marrakech is one of the main gateways to the Sahara, it isn't in the Sahara. Morocco + sahara or Morocco + desert might turn up better results.