I think it's common knowledge that Luther is one of the very few characters in the game not modelled after his VA, Evan Parke (it's says he provided his likeness in the wiki but honestly I don't see it)
So, who is Luther modelled after? He's not credited in any way shape or form, but I'm 100% convinced he's modelled after Bentley Kalu
I mean LOOK AT HIM, that's Luther right down the the distinctive forehead scar!
Evan Parke did a fantastic job of bringing Luther to life, but you have to wonder why Bentley didn't do the acting for Luther, especially considering the guy has even done voice acting for video ganes before! I mean, it probably just comes down to scheduling, but its weird that he's not credited for Luther's likeness. And damn you should hear his voice!
So, that makes 3 people who make up Luther, the third being Jua Amir Tutein, who provided Luther's (and Markus'!) singing voice and motion capture for the Hold On short.
Ultimately, this doesn't mean much, and I want to reiterate that I think Evan Parke did a phenomenonal job as Luther, and I'm not disappointed at all, I just find it interesting.