Thanks for the mention. I am not sure what it is. I want to say it is from Beethoven's 9th Symphony because you said it has been transcribed for numerous instruments, and Beethoven's 9th is also in D Minor. It definitely seems like it is from a development section because the key seems to be changing pretty rapidly from the music that you gave. However, it appears to be for piano and solo instrument in this case. The instrument obviously is in the treble clef, so that led me to believe it is from a Violin Sonata (either the first or last movement because it has to be in common time (or cut time), and be Sonata allegro (because it seems like a development). So therefore, I think this could be a movement from either of the Brahms or Schumann Violin Sonatas in D Minor. Good challenge! Again, thanks for mentioning my piece!