Just a heads up, Invensense IMU3000 chip is now available for purchase. It's a 3-axis gyro that's designed to be paired with a digital 3-axis accelerometer, and does sensor fusion on chip, removing the need for kalman filtering on an external MCU. Outputs are, besides gyro and accelerometer readings, temperature, attitude (as a quaternion), and lineair acceleration.
They sell a breakout board for $60 that comes with an accelerometer, so it's essentially a full IMU with handy I2C interface. I'm looking to get one but FedEx to the Netherlands isn't cheap, so if anyone is willing to share shipping costs let me know :)