The Turkish Arabian Empire
Although possible dual empires between Greeks and Turks has been proposed for multiple times by Turks and Hellenes alike, the difference in religion and collective memory has been proven too great to be bridged by a shared culture. On the other hand, the Arabs, no matter how mistreated by the Sultans, at least shared a common religion with the Turks. So, without the aggressive assimilation policies by the CUP (young Turk) leadership, as well as disastrous participation in the WWI, would a dual empire of the Turks and Arabs, in the fashion of the Austro-Hungarian Empire, be possible?
Let's say the Young Turk coup of 1908 was thwarted, and Abdulhamid controlled the empire until his demise in 1918, keeping the Ottomans out of the war. His successor faced an Arab political movement in a bid for greater autonomy, so he gave quarter to the Arabs, by marrying a Hashemite princess, as well as incorporating the colours of the previous caliphates (built by Arabs) into the new Ottoman Dual Monarchy flag.
The Dual Monarchy was bicameral, with an Arab as well as a Turkish chambers, the former included Berbers and Assyrians, etc, while the later also fielded Kurdish, Greek and Armenian delegates.
The Empire claimed heritage, as shown on the flag, of the medieval Caliphates of Islam . (The black was the
Abbasid dynastic color; white was the
Umayyad dynastic color; green was the
Fatimid dynastic color)