Laptop-sized psu/battery?

Hello, I'm looking for a laptop form factor powersupply/battery strong enough to power a gaming rig for 3-4 hrs. This rig would have a 8800GTX, and Quad Core processor. Any ideas on where to find something like that?

Thanks,
gimpster123

I'm not sure what you are asking. A laptop power supply is an external brick.

If you are looking for a battery to power that, you are going to be shelling out some cash or making your own. That is a TON of power to run that computer.

Just as a side note, you are not going to find a laptop sized one unless said laptop is the size of a car battery. Unless you are able to put this computer into standby, no way it is doing to happen