[quote=@gorgenmast]
<Snipped quote by Arawak>

The vast majority of this world is trackless desert; borders mean nothing here. What good is an empire when its vast dominion is comprised of nothing but shifting sand? Its all about controlling the trade, the resources, the settlements, the money. 
[/quote]

A Khanate would do well. But I think that would rely on draining resources from an older more established empire. Or something like that.