amBX style project idea?

Hi All, I am currently working on a simple two channel ambi-light (duemilanove only has 6 PWM pins). However in the course of this project I have started to wonder about other "4D Cinema" effects, such as the fan setup in the amBX premium package from Philips. Trying to figure out how I could sync a fan (or 2) with an audio stream - eg. Bass/LFE events triggering spin up, volume proportional to RPM.... However I am quite new to all this - does anyone have any ideas as to how I might achieve this or is it a dead-end?

Thank you for reading