These were played during the Nicovideo stream. some people took it to themselves to upload them. At least a 720p version of these now exists with these official uploads (the bitrate on the audio should be a bit better).
If there isn't going to be an official release (because that means someone else also gets money) it is the next best thing. Shame it came too late for say, Nintendo World 2011.
Giving Apple 30%? You must be kidding. Maybe the DeNA and Nintendo fun club spectacular membership rewards scheme will have digital soundtracks...
I think what Nintendo should do is open up their digital store more to allow people to purchase their OSTs digitally. Club Nintendo like rewards could get you the physical copy of an OST and before anyone else.