Actually, a lot of what you're talking about sounds like a branch of post rock
headed by Canadian
moguls Godspeed You Black Emperor!
and Dirty Three
and also Scotland
. Not very many vocals, though, but the same churning epic
melodies that usually denotes classical
In fact, Godspeed You Black Emperor! did Adagio for strings on their EP Slow Riot for New Kanada. So it's been done, and done well.