re: The logic behind a pressure suit?
Got me thinking.
Why do you need a pressure suit in a vacuum. Main reason is so you can breathe. So why not simply use a mechanical way of adding oxygen to blood- use a heart-lung machine. The astronaut undergoes surgery to get a "heart plug" which basically acts as a quick connect, so you can plug in the heart-lung machine in a emergency when you would otherwise need a pressure suit.
One problem is these machines are pretty big:
http://www.designnews.com/article/CA387440.html
But I doubt there is much demand to make them smaller, if there was some need for less massive machines they might be able to design them smaller.