I know these sites and there are indeed a lot of good midi files, but there are also not good midi files. Like old midi files meant for the souncards of that time. And midi files that sound as though the notes where just written in a sequenzer without further shaping (no crescendo, descrescendo, no differences in tempi etc.).
I understand of course that creating a good midi file is a lot of work. It\'s not only writing notes in a sequenzer, but also adding all effects, midi controllers etc. to make it sound realistic.
Do you know about music-score.com? I\'ve downloaded midis from them that were pretty good.
For example, Rule Brittania for brass ensemble(2 trumpets, trombone, tuba) sounds good with GS instruments, complete with velocity modulations.
I believe it is quantized, though.
Yamaha\'s e-piano competition included midi files of actual (real time) performances by some pretty competitive (classical) pianists. You\'ll have to google Yamaha or \"e-piano,\" perhaps, for that one. Strictly piano, of course.