There's rumor that Intel may be lifting their restriction on the netbook size later in the year, allowing larger screens on netbooks that use the dual-core N550.
Given that netbook sales have started to plateau, Intel is probably looking for a way to keep netbooks interesting by offering more form factors. It's also the case that Intel has been pitching the Pine Trail + Broadcom CrystalHD combo as a way to do 1080p video on a netbook—and 1080p certainly makes more sense for larger screens than it does on a sub-10" panel.
It could also be possible that Intel is foreseeing the coming wave of ARM-based "smartbooks" and Intel doesn't want the Atom competing with the ARM-based offerings. With the restriction lifted, OEMs can get to work on making larger Atom-based netbooks to hit the shelves soon.
This also raises the question of what makes a netbook a netbook? If the form factor is starting to resemble a traditional notebook, what's the difference?
Source Digitimes