How about looking a bit out of the north america?
The europeans have the bd, wich have some great artists, like...
Régis Loisel, of the franco-belgian school... He have a style not unlike DitErlizzi (spelling?) a bit, with a flair for a certain light comicish note and creative, but who can be quite dark at times?
Like the cover for La Quête de l'Oiseau du Temps - Le Rige.
Or the Frazette-inspired Gil Formosa, who have worked in the american comic industry? Very old-school stuff, he can do, if wished. Sword and sorcery.
Les Légendes du Chevalier Cargal was a classic of fantasy art in Europe
Or ledroit - Pontet, with their Warhammeresque impressive art in Chroniques de la Lune Noire, cool yet artsy at the same time?
Those guys could do wonders in Eberron...
The manga styles are not so liked, but well... There is some guys who could REALLY fit well with minimal efforts.
How about Tetsuo Hara? The seminial ultraviolent Fist of the North Star manga shown him doing an art inspired by american comics and artists (llike Frazetta) yet with his own feels. Also, he did among his other works a few famous samurai tales, like Hana no Keiji - Keiji the Magnificient. He could be well in an oriental Adventure book.
Hey, don't tell me that it would not fit perfectly in a new Oriental Adventures line...
Kentaro Miura of the classic dark fantasy Berserk fame could be good also. He do have his 'dungeonpunk' things now and then, but his art also have an occidental influence, gritty, dark side. Berserk was late medieval-renaissance anyway, so...
Is it very different from D&D?