Look, if they could all set aside their stupid religious squanderings, then I think it's possible. However most of them are so set on religion being the center of their governments that they forget about the people. I don't understand why certain governments (if we would call them that) seem to think that religion is the most important aspect to be connected to government. The country / state can be religious and moral while still keeping a seperation of church and state.
However as it currently is, the Shiites and the Sunnis are in too much disagreement over simple fundamentals of Islam to even come to agreement on religion. How can we expect them to unite into a single government?
I would support a united Arab state, when, and only if, religion is set aside as the key factor for running the government.