I am really surprised that more has not been done on this fascinating conflict; although, I suppose that the language barrier and the odd organizations and characters in that conflict would be confusing and off-putting to the English speaking world.

This war had just about everything that Hollywood would want: atrocity, bravery, static fronts with terrible attrition, then breakout and fast moving fronts, terrible sieges, character studies, conspiracy, Communists, Fascists, Nazis, Socialists, anarchists, democrats, bad Germans, bad Russians, bad Italians, bad asses, saints, sinners, ideology running rampant, religion and anti-religion, treachery, spies, international intervention, unique settings, beautiful scenery and so much more.

Not a lot here, at least not in English.  "For whom the Bell Tolls" is just average, "Land and Freedom" is a little below average, and if you slightly stretch a point you can include "Pan's Labyrinth" which is very good.