If you're going to do a dual-screen clam shell, do a palm-sized version of this:
http://www.engadget.com/2011/08/29/gscreens-spacebook-begins-shipping-this-november-doubles-your/
Really should only add the thickness of another screen. That is fine for business application use, but is annoying for gaming.
The largest issue with gaming on a side-side dual screen device is that your icon/character/avatar nearly always winds up in the middle with the bezel running through it.
There is a solution - but for a symmetrical application would require 3 screens.
Starting with the Thinkpad W700 dual screen:
http://www.engadget.com/2008/12/18/thinkpad-w700-surfaces-with-secondary-10-6-inch-lcd/
That 2nd screen is a side-car on the right. Put one on the left too. So, two slide-out screens that come out the sides of the lid in both directions that are about 2/5 the width of the primary (front) screen - to leave a bit for cables and mechanics inside the lid.
Now the kicker...
Make the center screen 4:3 @ 1280x1024. The side screens could each be 600x1024.
This yields a (600*2+1080) X 1024 screen = 2280 X 1024.
Of course the thing would be horridly fragile, require outlandish engineering costs, likely need highly custom screen components, custom graphics driver chips, etc... Completely impractical, but it wouild look really cool.
Then again, you could start with this as a point of reference.
http://news.cnet.com/8301-17938_105-9795471-1.html
Swap positions - single flap for a keyboard and use the dual side for monitors. Crazy complicated to build though - and looks fragile.