Hello,
Regarding chiru the information is classified
We are preparing a small feature update, however, and it will land pretty soon.
Regarding the PC tracks it is an interesting question, and previously we had some discussion on the topic. In most cases PS3 bgms have better quality as in better samples of the instruments or recording, so including the pc ones would not gain much if any improvement. Some tracks (e.g. tsurupettan or system0 with voices) are included as a bonus and appear in the Music box and/or in certain extra scenes.
If you still think this is not enough, I guess you could help us with both rondo and chiru by submitting properly named and encoded set of audio tracks. I.e. umib_XXX.ogg, 2 channel 48 KHz 256 KBit/s OGG Vorbis. If you take this responsibility onto yourself I will add the necessary scripting to support them.
Sounds like a deal?)