As a possibility I would throw the UAE/Oman and Saudi into the equation.
Desert Challenge is 2400 km long.
Oman can easily host the same distance with the inclusion of mountainous terrain.
Saudi bar the problems which may arise with female competitors has some awesome desert terrain.
Even without Saudi, you could host a 7000-8000km rally in this region and you probably would ride any track twice.
I even think the UAE Motorsport Federation has discussed this matter a few years back when the Dakar got cancelled. The former chairman is http://en.wikipedia.org/wiki/Mohammed_bin_Sulayem
They have the money, the period of the year would fit.
Not saying it will happen but it could easily. Start in Abu Dhabi, work your way to the empty quarter, 2-3 days there, stage up to Dubai, Dubai - Fujeirah, Fujeirah- Ras Al Khaimah, Mountains up to Dibba, Dibba to Sohar, Beach run from Sohar to Muscat, Muscat up through the mountains again and down. Muscat to Salalah, Salalah back through the mountains. It would be awesome.