Some pretty on-die water cooling, suggestions?

[sfa ok]

I looked at Spode's Sunny D cooler, and couldn't help but feeling inspired. I've been thinking of different ways of mid-priced water cooling for my Thunderbird. As I've said before, I always need something to do in my metals class, so I was thinking of machining one out of acrylic there. I hope the drawing gives you an idea of what I'm thinking, there's one input and two outputs that come back together outside the block. So, any suggestions on total volume of water in the block, and what could I use to cool the water? I'm planning to use some neoprene or something as a gasket, along with silicone epoxy to seal it, any chance of leaking (condensation not a problem, I can deal with that)? I'll post a picture of what the block will look like after being cut when I'm done designing it, probably tomorrow. Thanks.