Depending on you definition of "dictator," King Hussein of Jordan may qualify. Jordan is a Constitutional Monarchy, but there was a 22 year gap between 1967 and 1989 where Parlaiment was dissolved.

During his reign, he is credited with increasing the quality of life of the Jordanian people, dramatically increasing literacy rates and access to electricity, sanitation and clean water, decreasing infant mortality rates, etc.

Check out "King Hussein of Jordan: A Political Life" from Yale University Press for some additional reading.