This is a great idea. I was on the fence about doing this until the prospect of this thread came along. Now I'll definitely do it. Here are some questions that might help people know whether this is for them:
Can this be used to implement a 'return-to-home' function, especially in the case of a lost video and/or radio link (and yes, it can happen at the same time: http://www.rcgroups.com/forums/showt...0#post14835797
Can true airspeed be displayed on the OSD from the ardu shield?
Does this reduce the range of the Tx?
Would it work for a tricopter, especially the IMU part and stablization? I'm thinking of a traditional gyro-stabilized tricopter, not a computer controlled one, although maybe ardupilot would take over from the gyros?
Would it allow for the GPS coordinates to be encoded in one channel of the audio stream?
Does the IMU provide a variometer function?