I saw your series yesterday, they looked awesome. These are shot with a Canon 5D Mark II, not that many dead pixels in these RAW images, but just an overload of dust particles. I actually had to get it fixed in Stockholm because it was just horrible. Of course, they let me pay twice as much.
It's not persé the long exposures that cause me to see dust on my images, it's more or less the aperture that sharpens them.