Okay, basically i've built this block on quite a few ideas. First, let me describe the block. It will be approx. 10cm x 10cm for a P4. The size can be adjusted. Second, it will only be 1/8" to 1/4" thick (jaydee116 gave me the idea), with (hopefully) a 1mm base plate (Cathar's idea/philosophy). Third, when the water enters the block it will go through a + shaped impignment (Cathar's idea). It will then cool the pins in the center area. The incoming water will force the water to be pushed out of the channels, which will turn sharply into a "basin". Then, it will empty out.
Tell me what you think of the plan, the picture up there is for giving you an imaginative idea, it is a "crude" concept.