The Surface Pro 3 has been gaining a lot of ground in the business sector. We're beginning to move our C-level team over to these, and off traditional laptops. Using the Dock, you have a desktop or tablet depending on your needs.
I personally have mixed feelings about it. Win 8.1 isn't a great experience on a tablet at its maximum, prettiest resolution. It all works but isn't the smoothest experience -- when I'm in "laptop mode" with Typecover I'm effectively using a lighter laptop with a keyboard and trackpad that are acceptable, but not great... when I'm in "tablet mode" and using anything on the Windows desktop, I'm poking at tiny UI elements with the pen.
Still I can see Apple wanting a piece of this pie. We might see OSX on a slate ... and it probably won't be called an "iPad" so as to not confuse it with a device running iOS (the looks alone will cause some confusion anyway).