In between finishing up IHW:SC, have begun work on Outremer, a Blood Games II game set at the same time period as OHMAS, but in an explicitly alt-universe. In this setting, the Crusader States have managed to survive by balancing between Sunni, Shi'ite, and Ismaili Islamic forces, and by compromise and intermarriage. The Assassins (Ismaili) have carved out an independent state around Homs, Egypt is governed by a Shi'ite Caliph, and Bagdad by a Sunni Caliph. The Turks under their Sultan have taken most of Anatolia, except for lesser Armenia (Cilicia) which is allied to the Latin states of Outremer.
Islam will be fully detailed in the game, as will Christianity and Judaism. The Islamic section will differentiate between Sunni, Shi'ite, Druze, and Ismaili Islam, while the Christian section will differentiate between Roman Catholic, Orthodox, Nestorian, and Protestant Christianity. The Jewish section will differentiate between Ashkenazic, Mizrahic, and Sephardic Judaism. Not all the States of Outremer will be Christian. The intrusion of European culture and thought into the area caused shockwaves in both directions.
There will be new Paths of Power found here, coming from the different religions and from the interactions between the religions. There will also be new monsters. The Djinn will be very important, I think.
Hope this is of interest!