There are small chip based amplifiers like this one that I am looking for to put into my car PC setup. I'm sure they have stand alone small form amps that weigh next to nothing.
http://store.mp3car.com/TDA7850_Internal_4_x_50W_Quad_Bridge_Power_Amplifi_p/com-140.htm
That looks promising. Is there any way for me to add in an amplifier volume control knob? I have seen them before and that is what I would like to use.