With a POD no earlier than January 1st, 1900, have a functioning Arab Federation by the end of the century. Details (on borders) are up to you. However, it should contain at least (modern-day) Saudi Arabia, Oman, Yemen, the UAE, Qatar, and Bahrain.
Maybe if the British back the Hashemites in Arabia instead of leaving them out to dry, then the pro-British Arabian regime will be able to federally incorporate those holdings (Kuwait, Qatar, UAE) as the British withdraw. Yemen and Oman are a little harder, as those nations actually have, you know, national identities, but it might still be doable.
But would the Ottomans want to boost a vassal that much? They've already got the Egyptian Khedives as a bad example of vassals who got too big for their britches.