I doubt Satoshi would have been able to cover all his tracks.. Something like this is easily overlooked, besides, I doubt he was trying that hard in the beginning..
Well he's done a pretty good job so far. I think if you set out with the mindset to remain anon and know what you're doing it's not impossible. If I wanted to create a account with the intention of remaining 100% anon I think I could do it personally though wouldn't really have the need to.