Of rock players still knocking around I'd say the most impressive is Greg Howe, who started off doing Van Halen/Satch stuff but now is more fusion oriented. Check out his debut 'Greg Howe', his Van Halenish 'High Gear' and the fusion 'Introspection' to see what I mean. Boy has he got speed, as fast as Shawn Lane for sure.
1) Greg Howe isn't really as fast as Shawn Lane was.
2) But it doesn't matter, because its TOTALLY different styles. Greg Howe taps everything, while Shawn Lane hardly taps at all.
And I'd say he went through his Van Halen phase very early. He did a couple of albums with his brothers band (High Gear). But all of his solo albums except for the first one of course, have been very much fusion. I couldn't even comprare him to Satriani really.. he's just so much better (but once again totally different styles).
Tony McAlpine is also one hell of a player and has toured with Steve Vai. His solo stuff is a bit too neo-classical for my taste but he's done great work with fusion trio CAB which features Dennis Chambers on drums.
Tony's solo albums may be around 80% neoclassical. BUT, not only has he played with CAB, but he's been playing with Planet X for the past couple of years too!
I don't think these guys are underrated at all (except amongst those pigheaded Vai fans). Anyone thats actually HEARD Greg Howe or Tony Macalpine is very impressed (in my experience at least).