The Acer 11.6 inch C720 2GB RAM, 16GB SSDD is now $199 on Amazon's US website. I saw someone running Ubuntu on it, and it ran pretty well because it uses the latest Intel Celeron Haswell Chip.
The version of 2GB of RAM should be good enough sinch Chrome OS and Ubuntu are very light weight OSes. I think only user who open a lot of browser Windows, tabs, and Apps need the 4GB Chromebook.
I recently purchased an iPad Air and I'm in love with it. It has pretty much everything you're looking for too. I want to buy a keyboard for mine but that is on the list of things I wanna do. 😀
I like my Samsung Galaxy Note Tab 10.1. It has a stylus like you were talking about. I would recommend that or the Surface Pro, which also has a stylus. I would not recommend an iPad, because I feel that they are more limited in their capabilities (I don't want to start a debate about that though) and they don't have the stylus that you are looking for.
I have the Surface 2, and I sold my iPad Mini. The Surface is a great tool - especially if you buy the keyboard, too. I haven't pulled my laptop from my closet for probably three months. In terms of apps, it is a little lacking, but it is still a good tablet.
