IMO, RangerWickett wins the debate. Big sworded, big haired, violent, tentacled horror? Check. D&D 3e art may not be exactly in the anime style, but its alot more in that style than the obviously American style of 2e.
If I had the time, I could go on and on in the theme he opens up. Just because no one has really got it yet, doesn't mean it isn't there. I think people are going the wrong way about it. Although some of the paintings have it, the strongest evidence of manga influence is in black and white line art in 3e compared to manga and not to anime. Texture details in painted stills versus anime have more to do with the fact that one isn't intended to be animated and the other is than they have to do with general style.