Ok I've put some thought into the look, tell me what you think of this...
"Gritty graphic novel realism, with some stylised toon overtones"
I'm thinking "Sin City" film/comic but without toon shaders. Lots of dark shadow and highlights bloomed out to silver/white. As a pointer look at Caravaggio and the Chiaroscuro style. Hopefully with deep hues in between.
Reasonably accurate anatomy but with freedom to add come cartoon rule breaking (say exaggerated hands/proportions). Toon elements must be balance/contrast with realistic...so a slightly toon model will have gritty realistic textures and vice versa.
