That is really cool! It would be even cooler if we could speficy what key to play in, and which to switch between. Also the option to disallow weird* choords would be great.
*..and by that I mean choords (inclusive the melody - right hand on piano), that has notes which fall out of the scale. I knwo this sounds great sometimes, but I hear some pretty "interresting" (

) choords sometimes

A bit of improvement and this is really good! Very nice tool for 99% of the people in here (Cas and Marcus actually makes money

)
This is possible in the API. In my extremely simple GUI you can only specify a overall seed, arrangement and structure.
In the API and the original cgMusic you can specify separate generators for each part:
* harmonic rythm + seed for that
* melody generator + seed
* rythm + seed
* inner structure (phrases etc.)
* scale
* chorus/verse/no melody hints
* tempo change
You can for example keep changing the harmonic rythm seed until you like it and keep everything else intact.
If you try the original cgMusic, you can see what it possible to do with the API. I really recommend it since my GUI sucks

I have also heard this "interesting" harmony and the strange non-harmonic notes. This is probably a bug in my reimplementation of cgMusic or when the jazz-harmony generator is suddenly used which add 7th and 6th chords all over the place. If you combine that with a random diatonic harmonic rythm and a random scale, strange/sophisticated chords will be inevitable.
But you can have a lot more control over the music than my GUI suggests.