Interesting article, however I would say that five lines of C++ code per neuron is pretty optimistic considering the amount of work going into modeling a neuron in the blue brain project; http://seedmagazine.com/designseries/henry-markram.html
Also I remember reading in Code Complete that the space-shuttle software had zero defects per 500,000 lines of code by combining formal development methods, peer reviews, and statistical testing. Not really sured how they 'proved' there were zero defects, but I'm sure you could get the number far lower than 1 per 100 lines.