Two years ago, fredgsanford asked in the phpwsforums about black themes. Back then, no one had created a black theme. Until now, there's still not too many of those. Actually, I don't know of a theme that's totally black on black but that shouldn't be too much of a problem.

I tried creating a theme that's only gray and black, with a hint of green as an accent. You can download it here for free. Enjoy!