We’ve forked it and turned it into an Arduino library.
It still only supports “Port 0″ (the hardware SPI pins).
It supports the chip’s internal low-pass filter on the Gyro, default is 188Hz (defined in inv_mpu.cpp).
It still outputs Yaw, Pitch, and Roll. The fancy math functions (all that quaternion business) are now hidden (in mpu.cpp). It seems to work quite well, and since most of the heavy lifting is out of sight, the example sketch is easier to read and modify.