We used the company Saddle Skedaddle this spring, and can recommend them. They're a UK company, and offer guided mountain bike tours in Morocco. We used them for a self-guided trip in the English Lakes District, so we didn't "try-out" one of their guided tours. All the arrangements they made for us - rental mountain bikes, B&Bs, van transfers - went well, however.
I'd like to visit Morocco someday myself. My brother and girlfriend really enjoy the country. (They're surfers, though, not a bike riders...)