Spanish Oak

I recently heard from Pedro Barrera that Rafa Bernabé is experimenting with aging wine in Spanish (Navarra) oak. I recall reading that researchers at the Centro de Investigacion Forestal in Madrid have conducted experiments to determine whether wine aged in Spanish oak is just as good as that aged in American and French oak. They generally found that Spanish oak behaves similarly to French oak, which perhaps is not surprisingly since Spanish oak comes from the same species of tree as the French oak. As far as I know, there is no tradition of Spanish wine aged in Spanish oak. Perhaps the explanation is that there simply is not a large quantity of high quality wood of this type in Spain. Was there a time when use of Spanish oak was more common? Does anyone know of a wine that is now aged in Spanish oak?