I'm much more impressed by kids who can actually play and sing songs than boring kiddie shredding videos.
This video from 1969 was posted to YT in 2010 but is just now making the rounds among a few of my friends. I can't find anything else about them. Danish? Dutch? Music starts at 1:36.
The discussion also brought mention of this 2014 video. The band is from California. Another of their videos from two years earlier said the singer/guitarist was 9, the keyboardist 8, and the drummer 5.