Windows 8 Machine with good pen support?

Hello everyone, I'm currently a student studying mathematics among various other things and am currently using a Macbook Air 11in. I am deciding to switch (back) to a windows portable but I require a few things from it;

- Sound battery life (currently MBA gets about <4hrs of usage)

- Good pen support

- <13in screen size

By pen support, I mean I want to be able to lay the screen flat in some fashion or another and write on it with a stylus of some description, and preferably palm rejection. Some may find this archaic but I think it is really useful and what I'm after.

I've considered the Surface Pro, but that's amid keyboard woes (common complaints are that the Type Cover isn't wonderful) and battery life concerns.

can anyone help me out here?

Thanks