I don't know of any studies, but I do know that I was surprised to discover that I do use the touch screen on my windows 8 ultrabook a lot, frequently in desktop mode. I especially like to scroll by swiping my finger on the touch screen rather than by using two fingers on the track pad. Also it is often faster to just reach up and tap an ok or save button than it is to drag the cursor to the correct place and then click. Obviously if you have a mouse attached to the laptop that is faster than a track pad but not necessarily faster than the touch screen.
I would not want to interact with my laptop only through the touch screen, though. It is more like a useful additional feature that speeds up UI navigation as opposed to a stand alone way to navigate the UI. This is because not all the actions you can take in the OS have been assigned an efficient way of being taken through touch.
I also have an 8" windows tablet. I almost never use a mouse to navigate it - instead I use a pressure sensitive stylus, which is somewhat different than touch but is a similar premise. Handwriting recognition is excellent in Windows 8 so I can easily take notes and can edit documents to some extent although the mouse is better. I downloaded a program called Touch Me which allows me to assign actions to various gestures and to customize the touch screen experience.
I hear what you are saying about the size of the motions required to navigate larger screens although you usually don't have to swipe all the way down to pull down notifications... A few inches suffices. If you root your tablet, you can install an app to assign actions to gestures and you can design how much of a swipe/gesture is required, and the gesture will perform that action from everywhere (ie not just on the home screen). You can program some gestures without rooting on android, but they won't work everywhere. For example buzz launcher's gestures only work on the home screen.
