Reader Richard Baron writes:

You mention Numminen's performance. Let us not forget Elisabeth Lutyens' motet, opus 27: 

https://www.youtube.com/watch?v=6tVjyYY4hRg

For those who wish to pursue this topic, there is at least one article on the piece:

Parsons, Laurel, "Music and Text in Elisabeth Lutyens’s Wittgenstein Motet", Canadian University Music Review, volume 20, number 1, 1999.

I have not found a DOI or Jstor stable URL for the article, but it is on Questia, here:

http://www.questia.com/library/journal/1P3-1600760701/music-and-text-in-elisabeth-lutyens-s-wittgenstein

There is another piece of Tractatus music "A Picture of the World", by Anthony Powers, but I have not found it on Youtube.