Not been around much lately, and only just saw this thread. *sigh* - I could have got all the previous ones. Being a bit of a score obsessive has its advantages. Larry's latest:
7) - Rzewski - The People United.... (btw, there are some great free Rzewski scores to be had online)

- Brahms G major sextet op 36 (last mvt)
9) - Wozzeck - Act III interlude (climax thereof)
10) - is indeed Mahler 9
11) - Le Marteau sans maitre
12) - this is the only one eluding me at present
13) - Carter, Quartet no 1
14) - orchestration, figuration and textures (and print style) look like Shostakovich (#14?) though I can't place it off-hand
15) - is indeed Orfeo