Do NOT start swapping laptop CPU's, even if you could.
There are PLENTY of laptop configurations. Plus, any laptop with a good graphics chip will have a good CPU to support it.
A great, light-gaming laptop costs $700.
Anything above that is basically better CPU and Graphics for better games, so it boils down to how much you wish to spend.
Since anything considered a half-decent gaming laptop starts at about $1000 I strongly suggest you don't crack it open, VOID your warranty and end up with $1000 of spare parts.
Summary:
- choose your budget
- pick a laptop with the best GPU in that budget
- make sure it supports NVIDIA's Optimus (two GPU's. Turns off the gaming GPU when not needed to save power and HEAT.) Absolutely do NOT get a good graphics card without Optimus. My brother-in-law did and the HEAT is annoying when even typing when not gaming!
- avoid ACER (recommend ASUS first. Others are Toshiba, HP, Lenovo..)
- other: screen size/resolution, USB3, eSATA, 1 or 2 hard drive slots? (nice for backups though only 17" have 2.) etc.
Kepler:
Some 6xxM series are the new Kepler and some are not. I believe the 660M and 680M are Kepler. The best value, once available, might be a laptop using the 660M chipset.
*As long as you are aware of the cost and relative performance vs a desktop that's fine. I just had a LONG discussion with a friend who decided to get a quad-core APU laptop for light-gaming but mainly school. It sits in his small dorm room, is basically silent and cost $600. He also hooked it up to a Samsung 22", 1920x1080 monitor via HDMI to get video AND sound, and uses a Logitech mouse/keyboard with the micro-USB connection so he can leave it in at all times even in his case.
He plays these games on his $600 laptop:
Torchlight, Angry Birds, Sam&Max, Bastion, Magicka, L4D2 (not sure of settings), Super Meat Boy, Serious Sam HD and Command&Conquer 3.
(He's pretty pleased and got all his games, on sale, at STEAM.)