If ya wanna get into some basics of 8 finger tapping, you can check the later lessons in the link below. I haven't gotten around to Part 5 yet but eventually I'll continue on with more techniques on 8 finger runs and scales.
As far it being rare I'd probably agree, but I don't know if I'd call it a novelty. I've been using it in about half my playing for years now and rely on it as a legitimate playing style just as I would sweeping or any other technique.

All About Tapping: Part 4

This song uses 8 finger tapping in about 50% of it...mostly for runs and sweep-like arpeggios

http://www.schmange.com/MoogBoog.mp3