I agree that the surface pro is pretty cool, and the logical conclusion of the tablet market. Unfortunately, it's still a bit too expensive for the mainstream consumer. If they could get it down to the ~$600 range, you could justify buying it over a cheap laptop.
I'm not sure that we'll ever see an OSX equivalent. As apps become more and more sophisticated, there are fewer and fewer needs for the "full-fledged" OSX. Of course, I do not think iOS will replace OSX either. Perhaps if we are lucky, we will see an iOS+ mode one day, in which you can dock an iPhone/iPad and run OSX with a keyboard/monitor/mouse. I am doubtful even of that, however.