Go and take a listen to some of the players at guitar nine records. There's no direct way to compare them 'cause they aren't playing the same passages. It seems to me that there are a scary number of people who can play as fast as Malmsteem, Wylde, Pettrucci, Vai etc. I can't honestly tell the difference. They all hit their limits around 25 notes/second.

One notable player who hasn't been mentioned is Tony MaCalpine - try "Evolution", this guy plays Chopin on Piano brilliantly and pisses on most guitar shredders. Shaun Baxter is a tremendously capable british jazz/rock guitarist but sadly I hear that his album Jazz-Metal is ot of print which sucks 'cause my copy got nicked.

The players who really stand out for me mix their velocities up all over the place. A burst of one or two seconds says as much about your speed as anyone needs to know. In terms of raw technique try "Rustey Cooley", he can sweep pick up and down the neck at speeds that most of us could only cope with in a single crossing of the strings.