While the below example doesn't exactly fit the parameters of the question, I think it demonstrates a racial open-mindedness that wouldn't be found in many European monarchs who lived in recent times, and perhaps some alive today.
In 1536, Charles V, the Holy Roman Emperor and ruler of the Spanish empire, married his daughter, Margaret of Austria, to Alessandro de' Medici, Duke of Florence ("Il Moro"), who was the bi-racial out-of-wedlock son of Lorenzo II de' Medici and an African servant in the household, Simonetta da Collevecchio.
While de' Medici did not have any children with Margaret (he did have a child with his mistress) during his short life, the mere fact that Charles V sanctioned this marriage is worthy of note.