Monoprice. They are made by OKGear and can be found at pretty much any parts store. Newegg has them, Micro Center has them, etc. They have a variety of colors, and you can get them in 18", 24", or 36".
Just stack about 20 rads, mounted in the front, so they extend all the way through the case. Should keep your CPU icy chill, assuming you can afford enough fluid.