I don't know if it qualifies or not, but I recently discovered Hawkwind (circa 1970) and while it's not as lyrical as favoured prog bands, it has that "Oh, I really like this and it's only halfway through the 15 minute track".
An entire concept about a sad doomed swordsman, last of his elfin kind, wandering the multiverse with a sword that eats souls.
It is possible to get proggier than that but this is a feat few mortals can attain.