Hellcow
Adventurer
And in Eberron, you have two friends on this front: the Last War and the Dragonmarked Houses.Imaro said:A sense of urban grittiness and corruption that permeates the "scenery"...there's more but I'll stop here.
As I play it, the Last War hangs over EVERYTHING in Khorvaire. The war only ended two years ago, and no one believes it's over for good. Scars of the war can be seen across the countryside. The people of that village you pass through may hate you for your nationality, because of what the Aundairians did in the war. For this reason in particular, I always encourage characters to explain what they did in the war (again, still going on just two years ago), or if they weren't involved why they weren't involved. Here's where you can get your flawed and ambiguously moral heroes. Did they do anything they now regret? Did they lose their faith in their religion or their nation? Did they lose their entire nation, if they were Cyrans? If you participated in a massacre while fighting for Cyre, can you BLAME the Brelish villagers for hating you in the present day? The scars of the war never go away. You may have been fighting for a cause you believed was right, but so were the people you killed. And their children may be hunting you down today, or their queen may be preparing to start the war again.
Beyond this, we have the Mourning, the unexplained mystery that still threatens the world. As no one knows what caused it, no one knows if it will happen again. The world as you know it could end tomorrow in a cloud of dead-gray mist. How does that affect you? What does it do to the morality and aspirations of the common man?
Then we have the Dragonmarked Houses - the chance to bring urban grittiness and greed even into the wilds. You could be in the Talenta Plains, but you're still dealing with House Orien's hunger to expand the rails and claim this untapped land. Or perhaps it's House Tharashk, seeking to eliminate a native tribe to lay claim to the rich dragonshard deposits their finders have located. Or House Cannith, seeking to reclaim an aerial weapon lost from the war - something kept hidden even from the kings and queens of the Five Nations, something they were saving to serve their own interests. The houses aren't about good or evil: they are about profit and power, and they can seek that anywhere.
I agree that few sourcebooks have addressed this - though in regards to the scars of war, I would add The Forge of War to your list. But to me, the foundation for noir is there in the deep wounds left by the war, the overaching sense of doom created by the Mourning, the slow but continuing collapse of the feudal system and the grasping ambition of the Dragonmarked Houses. I think the dominant feeling at WotC may be that more DMs prefer the pure pulp, because it IS something D&D does very well; but the anchor points for noir are certainly there in the world.