Although he can shred with the best of 'em, David T.
Chastain has largely flown under the radar.
That said, he's certainly known within the guitar community (as he's received a fair amount of coverage in instrument magazines since the '80s); if you're not a metal guitarist, you may not know of Chastain.
And if you're a fan of six-string-heavy instrumental music, then you're missing out on a gentleman who can certainly hold his own with the Greg Howes and Vinnie Moores of the world, as evidenced by his 2000 release, Rock Solid Guitar.
While some guitarists of the "instrumental metal" genre tend to be a bit one-dimensional in their approach, Chastain manages to mix things up a bit here, by touching upon songs that are blues-based ("Sounds Cool to Me," "Keeper of Tomorrow," etc.), as well as tracks that are comparable to Joe Satriani ("Burning Passions"), Steve Vai ("Dancing with the Devil's Mistress"), and even a tribute to AC/DC's brother guitar tandem (the appropriately titled "Hats Off to Angus and Malcolm").
He may not exactly be revolutionizing rock guitar, but David T.
Chastain certainly has the chops to hold his own against the aforementioned metal/rock guitarists, as heard throughout Rock Solid Guitar.