I am also coming to the conclusion that you end up blending shots to get the final result. A single exposure is good, but not good enough.
The shot below was taken the same night when all the clouds moved on. The stars looked so beautiful and due to the rain, the sky was "dust free".
This one is not a nightscape, and I left it slightly dark - but on my laptop, the light shines nicely through the image. I think I used two 20 second exposures loaded them as HDR images in a trial version of CS6 to see what Photoshop could do.
hmmm HDR huh? never heard of that technique in a milky way shot