You should also take my comments with a grain of salt because my hopes for things like this are for lack of a better way of putting it musically bound. I can't help but listen to this as art, and so I'm responding to it that way. I'm taking these pieces as things for close listening.
I think making long renders for static streaming is a fine approach by the way - have you thought about automating a re-render more often for each piece?
A more expensive alternative would be to run a dedicated render server to generate music in realtime, and then multiplex the stream on demand with something like wowza. Makes me miss the days of r4nd.org: http://rhizome.org/discuss/15607/#29894
Good luck with the project & thanks again for sharing!