Still things to do, but this may really be useful. I used it for one composition, and it worked so well, that I didn't need even boot windoze once to complete this piece. As plugins started to work in snd, which is by far the best sound editor available in Linux, I wrote a simple utility to ease their use. The recent snapshot of guile-tcltk didn't work, so I implemented this with wish. The new version includes butterworth-plugin.
Fractals give quite nice sounds.
Here's a cm-utility to generate midifiles from fractals. Several fractals are included in the file. Download Midi example of Lorenz attractor. No docs available, you just have to figure out how it works, sorry.