I use a water cooler for my QSI 540wsg camera and find it helps a bit , giving about another 10 degrees of coolth. I made a portable supply unit, built into a 12 litre (I think) Esky. An immersed 12v pump together with an immersed Aquarium cooler to give additional cooling. I've a feeling that the immersed pump puts just enough heat into the water to counteract the aquarium cooler so the design probably needs looking at!
Charles