That's an interesting question, Dag.
That System Shock 2 example, is it just a bunch of files, without a proper a tracklist or tracknames? I think for something to be added, there has to be something to actually add, if you see what I mean.
This here is a good example of a composer released cd-r that would warrant inclusion.
Similarly, he Okami "retro version" consisted only of a bunch of mp3s, with no official track numbering (as far as I can remember). I'm not even sure if the 17 tracks I found were all there were on the site. As for other "mp3's officially posted on a website" releases, we already have at least
one of those in the database already...