GTX 460 @ nouveau: 2 watts
GTX 460 @ blob: 13 watts

Your explanation: "this may be due to the Nouveau driver not initializing all areas of the GPU"

Really ? *Maybe* it is because all areas of the GPU are clocked at 1/10 of the frequency the blob drives them at ?
Don't you think this is kind of *important* information when doing a *performance* comparison ?