Hi Everyone,
I took a different approach to solving this battery problem and the dual GPUs on the Macbook Pro 2011 model. Since we are stuck with using the Radeon HD 6490M GPU, I thought to just optimize that GPU for battery life as other laptops use that GPU with no battery issues.
There are several versions of the 6400M GPU:
http://www.notebookcheck.net/AMD-Radeon-HD-6470M.43075.0.html
Each have a different clock speed. The clock speed is set by the driver inside windows. The 6490M runs at 750MHz GPU/800MHz RAM. The 6430M runs at 480Mhz GPU/RAM ???. Ideally we would want to use that driver or underclock the 6490M driver to 480Mhz and we should get better battery life. Yes, it would decrease the performance but I personally am not a gamer and don't care for 3D performance.
I tried various tweaking applications to lower the clock speed to 480MHz and to install the 6430M driver for the vide card, but was never successful.
I did however find another laptop that uses the 6470M GPU, this is the HP DV6TQE or "HP Pavilion dv6t-6000 CTO Quad Edition Entertainment Notebook PC" if you go to the HP website. On the HP website (as of writing this post) they have a driver from February which is later than the current bootcamp drivers. The name of the file is "sp51585.exe". I tried those drivers and it installs the 6490M as a 6400M and I saw an increase in battery life from 2hrs 52m to 3hrs 22m (windows taskbar). Small 30m increase.
I also started digging for other drivers 6400M drivers and came across this driver:
http://driverpacks.net/driverpacks/windows/7/x64/graphics-mobile/11.04
Those drivers are dated 3/8/2011 and show a total time in the taskbar as 3hrs 50m on my 2011 Macbook Pro 15" 2.0Ghz. That's the best result I have had after 3hrs of trouble-shooting, and that is what I recommend. Hope this helps everyone. If someone is successful at underclocking their video card in Windows 7 to 480MHz, please let us know.