If you guys have played the game Slender, some of you guys know that after daytime mode there is $20 mode (video link below). I think it would be pretty sweet to have a mod where if you are a certain distance away from an enderman, the music would play like in slender. Also, getting louder as you get closer to them and visa versa. I've seen a few mods where you can put music in game using audio streams. I don't know any java, so I don't know if there's a variable that you can read that gives you position of the nearest enderman from player. But if someone could work that out that would be great!
Not quite. It is possible to do with midi files as I've done here. Whether the track will sound any good or not varies with many factors.
Depends how good your midi composer is. If you're relying solely on a program to convert the sound you're absolutely right. Of course, translating that again into note block sounds is another matter.
Yeah, I was actually thinking of that possibility while I was typing my post. That's a different sort of thing, though, and it's pretty much impossible to keep the quality high enough for legit music in this case.