I've listened to a lot of these and the best preteen I've heard is this at 10yrs old and female: http://www.youtube.com/watch?v=tOL6q...eature=related
Another from the same 10 year old, this is killer: http://www.youtube.com/watch?v=6TIq6...eature=related

It's amazing some of the stuff you can find on U-tube, but begs the question...will any of these ever make it to the big time?