That would be 2560x1920. ChromeBook Pixel has a 2560 by 1700 display, which makes for a wider aspect ratio of almost 3:2.
Last time I had to deal with non-square pixels on x86 was when programming mode 13h graphics for DOS at a 320x200 resolution (which was then stretched to 4:3). The only thing that comes to my mind that you could do now with modern equipment would be to connect your laptop/PC to a bargain bin plasma panel that has a 1024x768 physical resolution and achieves a 16:9 aspect ratio by virtue of non-square pixels [1]. My first encounter with one of those caused me trouble when I wanted to use it with a Linux PC some time ago.
[1] http://hometheater.about.com/cs/television/f/aaplasmafaq5.ht...
Edit: expanded first paragraph.
I'd rather have 4:3, and my current laptop is a semi-custom Thinkpad I built by shoehorning a newer motherboard in to a T60p just so I could have a decent 15" 4:3 screen and 8gb of memory in the same laptop.
Unfortunately, this particular machine is a little pricey for what it is and not a size I'd like. It should diminish the "these are the only screens we can get" excuse that PC makers keep trying to give us though.
I am disappointed though. One of the images they showed was in low light and it made it look like the whole surface of the keyboard area was charcoal sort of shade. I think that would look way more sleek and professional looking, and at the same time it would help to differentiate it from Apple products.
Other than not having a touch screen.
http://www.theverge.com/2013/2/21/4013480/google-chromebook-...
It looks an awful lot like a Macbook: Just witness the aluminum-like color and the black bevel around the screen. Where it looks different, it's uglier. The hinge looks particularly bad. And judging by the pictures it's an awful lot bulkier than a Macbook Air.
Chrome OS strikes me as an underpowered OS. That is, there's a lot it won't do and it seems mostly suitable for underpowered machines.
UPDATE: this paragraph is wrong; I stand corrected! -- The ChromeBook Pixel has a 4:3 display. Now, I recently came across an old laptop of mine that had a 4:3 display and it looked off. I'm not saying that 4:3 aspect ratio a bad choice in an objective sense, but it strikes me as a bad choice from a marketing point of view.
For one hundred dollars less you can get a 13" Macbook Air. For two hundred dollars more you can get a 13" Macbook Pro with Retina Display. Both these machines seem better than the Chromebook Pixel in every way, including battery life (7 hours versus 5).
In conclusion, I think this is going to fail badly.