ChaosTheory is a dark single-column theme with a minimal, techy feel.
Ghostbird is a blue, beige, and red one-column theme for WordPress.
Nelson is a fairly minimal design that should be easy enough to customize to your own liking.
TwentyTen Five is a variation of the TwentyTen Theme with many modifications.
Chaos Theory is hardly new… it was available last year.
ChaosTheory did launch as a WordPress.com exclusive in 2007, but it wasn’t released to the general public (self-hosted WordPress) until a few days ago.
Thought it looked familiar, I had used it for a short-lived WordPress.com blog.