Are there are quad head water coolers out there? That might be interesting.
Would go with 4 individual blocks, linked 2x2 is seriers to 2x 240 Rads.
Blocks: 4x http://www.frozencpu.com/products/16395/ex-blc-1153/Alphacool_NexXxos_XP_Light_CPU_Liquid_Cooling_Block_-_Acetal_Edition_-_Intel_AMD_12153.html?tl=g30c325s1118
Pump: 2x http://www.frozencpu.com/products/9898/ex-pmp-92/Bitspower_Mini_Water_Tank_Plus_DDC_Pump_Attachement_Reservoir_w_Filter_-_Acetal_Cap_BP-DDCT2-CL.html?tl=g30c107s152
Rads: 2x http://www.frozencpu.com/products/14327/ex-rad-315/XSPC_EX240_Dual_120mm_Low_Profile_Split_Fin_Radiator.html?tl=g30c95s160
I know its expensive and highly impractical.. dont care.
Plus you can pay in BTC