i am surprised no one mentioned bartoks piano pieces, his piano sonata and his first and second piano concerto are really violent pieces.
also, prokofievs second concerto has some really violent momentts , the cadenzas specially.
i dont remember the name exactly , but i heard them in a cd by angela chang playing messiaens piano music, i think they were two of the etudes , something like rhythmic etudes by messiaen, they wer eboth pretty violent, specially the second one.