I guess the Forum is partially correct. You might want to add "on a Laptop" in your thread Title for faster understanding of the topic / attracting more specific Users.
Sadly I don't know much about nVidia, even less about Mobile GPUs.
If you had a Display port MultiStream would work. But this technology doesn't work on HDMI.
Maybe with a DualHead ?
http://www.matrox.com/graphics/en/produ ... igital_se/P.S an USB Display will never work as youre not using your GPU for these devices but the graphics render inside the Monitor. So technologies like AMD Eyefinity or nVidia Surround are not available.