Faure did write a Requiem, though. I hardly consider that a small work.
But at the same time it hardly qualifies as "massive" and the piano is certainly not involved in it. He also wrote a considerably larger work in his one opera
Pénélope, which has about two hours of music altogether but, again, "massiveness" is far from the first thought that comes to mind when considering it; Strauss's
Salome and
Elektra, each from a few years earlier, are each shorter stage works but truly massive in every other sense.
Anyway - back to the topic!
Best,
Alistair