Although I don't have the Medina surname in my tree, I have also been curious about it because the name is common in northwestern Durango. I have various books about northern Mexico in the 1600/1700's, and information about early settlers with that surname has never turned up.With the Inquisition being a powerful institution in Mexico in the 1600-1700's, it seems a name like Medina would have aroused suspicion of a non-Christian background. Maybe a search on the Pares website will turn up some clues.
Medina Surname
Having a surname based on a word that was introduced to the Spanish lexicon 1,000 years earlier by Moors does not mean that they had a high likelihood of being a descendant of Moors. The Moors did not even immigrate in high numbers to Spain. They controlled a large territory of Spain but their numbers were small in comparison to the populace. In 711 AD when the Moors invaded Spain surnames did not exist as they do today. Once Christians reconquered Spanish territory they did not rename all of the towns and cities. People began to use surnames about the same time of the reconquista and many times the surname was based on the place they were from. Since there were many places named Medina many families adopted the surname Medina. Most of these families were Christian families and therefore there was no reason to suspect these people of being Moriscos. Having a surname of Arabic origin should not cause an assumption of Moorish or Arabic ancestry.
Armando