I have seen that Tool cover and IMHO it is awesome. This youtube video is pretty sweet also http://www.youtube.com/watch?v=RPgGFXx4efA

Russel has some serious pipes! more than a few years back I was at my friends house (he was buddies with Russell) I was in his living room playing his guitars and unknown to me Jack showed up and was in the room. I was playing over the hills and far away and he started singing the lyrics - His voice is so powerful and he sounded so awesome I nearly fell off the chair and had to stop playing to see who this incredible voice was. My buddy fell down laughing at the look on my face.

Jack Russell from great white could pull it off cover of Babe,I'm gonna leave you http://www.youtube.com/watch?v=Qs_BNunyIMI Since I've been loving you

This may be old news to some of you but I just heard Jack Russell from Great White cover some zep songs and he does an awesome job http://www.cduniverse.com/search/xx/music/...ed+Zeppelin.htm If Jimmy Page is looking for a singer he should give this guy a try