I have a G15 and took off the wrist rest that came with it and replaced it with a gel pad. However, I agree with KC, I don't use anything for the mouse.
I did the same with my G15 when I was using one. Now i have the cordless logitech wave, and the wristpad that comes with that is quite nice.
As for the mouse. I only use it when I am not gaming. There is nothing worse than playing FPS, you need to move the mouse down suddenly to shot some one. However you are stopped by this gel pad. Only to get owned by the person that you were trying to aim at.
Death By mouse pad
then again, there are those mouse mats that weeboos use where you have some anime girl and her boobs are where the wrist support is.
I know one person that seems to have a collections of these. And I guess he wonders why he does not have a girl friend.