Sounds like you're describing 'A Bridge Too Far'. It has an ensemble cast and some well-executed battle scenes with tanks. The score is composed by John Addison, who utilized strings quite heavily. It's World War II, strategic, and has very distinct cinematography.

I had a film professor who was obsessed with lost films, especially 'Silver Eyes'. From what I remember, he mentioned an Italian collector who passed away in the early 2000s, and rumor has it that a copy was found among his estate—but nothing came out of it publicly. Might want …