Director John Singleton has given an interview to comicbookmovie.com, in which he expressed his frustrations at the long-gestating Luke Cage project. Wikipedia has a nice summation of the development history of the film since June 2003, if you're interested. When asked directly by the interviewer why Sony isn't jumping on this project and turning it out quickly, Singleton seems to lead with his gut reaction before pulling back a bit: "Well, because it's a black superhero and so studios still, some studios, don't understand that yeah, it is a black superhero but so what? He's a superhero. That hasn't been done yet."
He also adds the following: "We have a great script. We have a couple of great scripts. It's just a matter, like I said, some people have not got it yet. I'm not saying every studio on the board, some people haven't got it that multi-ethnic sells." Singleton also gives a rundown of what must be the most current synopsis of the project: "It's basically a guy that gets out of jail, basically breaks his way out of jail and he's basically a superman. He has to learn to be a hero for the sake of being a hero, not because somebody pays him to be a hero. What would an ex-con do if he had powers? He'd go back to the neighborhood and be like 'Okay, yeah, I'll help you but you've got to pay me.....he's going to be kind of a thug but then he's got to realize that you do things for the right thing, not just for profit."
The actor most often linked to the role of Cage is Tyrese Gibson, although the Wikipedia summary says that as recently as August 2006, he had not yet made any commitment to the role. Interest may rise if his performance in this summer's Transformers is notable. Terrence Howard is also rumored to be in negotiations to play the main villain in the film, a Cage foe named DiamondBack.