When I saw this video about a week ago, I also thought it would be a good mix, but the sound of the video is TOO BAD for make a decent mix. In addition, the tempo of the piano cover is a bit lower than the original version, and that makes the mix sound a bit distorted, even if you regulate the tempos.
I tried to, but the result was a distorted 64kbps MP3 file which only deserved being thrown to the bin.
that's a pretty cool idea though. why not redo kite with the studio version playing on headphones, and perhaps with a better recording system? then the tempo will be perfect for the remix and with better audio it could be another cool version to hear...