The current code has a delay of 100 ms after each bit sent, so the current rate is about 10 bits a second. However, according to the product video, the sensor has a max speed of 3300 cycles a second, so in theory, you can get up to 3 kilobits a second provided your magnet can turn on and off at that speed.

That's a very good point. You'd probably be better off with some other technology.

I like the idea of adding additional sensors, but how would you mount the tilt sensor to detect movement? Maybe you could just activate the accelerometer function of the LSM303 in the code?