personally if i was to build a system like yours i would get a bix 2 or a shrouded heater core with a cooling surface of 9"x6" with two 120 mm fans, a swiftech mcp600 pump, and xeon converted maze3's or d-tek white water waterbllocks. all plumbed in series for 1/2" and housed separately.
here is a link to a heater core that would work great.
http://www.partsamerica.com/PartDeta...pe=524&PTSet=B