[@The Harbinger of Ferocity] I don't really see why it would need a port of the full comprehensive list of changes you made to 3.5e. I'm not sure what you did with lore but as far as mechanics all you really need is to make the hp and spell slot regeneration systems less forgiving and throw nastier bads at people to make a campaign feel grittier. In my experience, 80% of the grit for any system is setting and tone. 

Look at Eclipse Phase, a sci-fi tabletop that's basically made to play off cosmic/eldritch horror. In that game you can have your physical body die as much as you want and it doesn't matter, what matters is the psychological state your mind is left in after all the shit you've just been through. 

For reference, Eclipse Phase is in a far-future scenario where humankind has transcended the need for their natural bodies because they managed to digitize their minds and implant them in manufactured bodies. Mechanical, biological, biomechanical, alien, whatever. So if you die, you can just have your mind be recovered and downloaded into another fleshy sleeve and keep going. The point of this is to show that the new list of dangers taken form by the advancement of technology is far more terrifying than something as mundane as death. Put that alongside the fact that resources in the game are far from plentiful because the solar system is on the brink of collapse. You have to be careful about what you get because everything is a finite resource. 

I might have gotten a little carried away and I don't plan on making this thread into a different tabletop discussion. The point is that you don't [i]need[/i] to change every little mechanic to make things gritty and have the world brutally indifferent to the players' existence. All you need is to put them in the right situation where everything is not plentiful and even if you get out of the situation physically unscathed you're still far from fine. 

Or maybe I'm being dumb. Maybe I just wanna play EP now. Whatever. I'm going to focus on this RP now and if you make your own campaign then do what you want with it, I won't bitch at you. Promise. I'll probably still try and join up regardless of what you do with it.