It seems a lot of guitarists have started four finger tapping like this. The first artist I ever saw do it was buckethead. It blew me away then and as a casual guitarist it blows me away these days too. I know what they're doing but I don't have the dexterity to pull off dual hand 4 finger tapping.
Have you heard of the Chapman Stick? It's an electric guitar-ish instrument designed specifically for tapping.
It's a very neat concept. I wouldn't mind learning to play it, but they're shockingly expensive, and obscure enough that I doubt there are many resources for learning. They're very cool, though. EDIT: Here's another good one:
Heh it was a bit of music nerdiness. Buckethead really likes to play with dissonance and it's an acquired taste when it comes to listening. You'd probably appreciate some of his more melodic stuff or some of his softer stuff.