Slightly off-topic, but I have a Skookum SK-720 flybarless controller on my helicopter. It has 2GB of internal flash and logs all gyros and accelerometers (it has 3 of each) for post-flight analysis. Only weighs 17g too.
You can always take screenshots of each graph for comparing later.
I think a stand alone solution would be better than getting one or two developers to implement it on their boards. I know that I would like to use something that is a lot smaller than my phone, that can be placed just about anywhere on the craft.
So I ordered the Tiger motors for this quad today (MT-4006-13). Strangely almost no one on the planet seems to stock them but I finally found a shop in Poland.
I was able to run a vibration test with an iPhone and the "Vibration" app installed. I flew two hover flights with the QAV500 at about 6 feet inside. No wind, but maybe still a bit of ground effect and air being pushed around in the room. For one flight I strapped the iPhone to the top/clean part of the frame and during the other I strapped the iPhone to the dirty/bottom part of the frame. See the results of each in the below picture.
Tim, now you are just teasing us. The graph comparison looks fantastic!