I know that Prince Adalbert of Bavaria (youngest son of King Ludwig I) established the so-called "Spanish" branch of the dynasty: he, his eldest son (Prince Ludwig Ferdinand), and the latter's eldest son (Prince Ferdinand) all married Infantas of Spain. The latter (a grandson of Queen Isabel II and brother-in-law of King Alfonso XIII) even renounced his succession rights to the German kingdom and was given the title of Infante (with the qualification of Royal Highness) of Spain.
Interestingly enough, his uncle (Prince Alfons of Bavaria) also married a Bourbon princess; but his wife was French, not Spanish. In any case, there seems to have been a surprising number of intermarriages between the houses of Bourbon and Wittelsbach, given the linguistic and cultural barriers ... But then, they were all Catholic houses, and prior to World War I, members were expected to marry "equally", for royal unions to be dynastic.