More portable than the M200?
Can you say more about what that means to you?
Better battery life?
You aren't going to get them all in one machine and you are likely going to take a step down in terms of screen resolution. You had 1400 x 1050.
There are several machines that will give you some combinations of factors like battery life, faster, high resolution, but they won't be smaller or very much lighter.
But if you talk about what you mean by more portable, maybe some suggestions will arise.