I plan to stick a peltier between each heatsink and waterblock. I will connect to waterblocks in parallell. The 3/16" connections on the Koolance WB makes this a must.
The whole thing will be mounted on top of my case. As the pictures above demontrates. Some kind of frame will hold the heatsinks above the top of the case so that air can flow up through the fins of the HSs. If necessary, which is likely, some quiete fans blowing air from beneath will help convection.

I am not sure how I will control the power to the peltiers.
I have been thinking of using the CPU-fan control output voltage as a control voltage for a mosfet powertransistor that would control the voltage fed by the extra PSU to the peltiers. To bad I dont know enough electronics to know if this would work.
This method should allow easy control to run condensation free, but still keep the system just a few degrees above condensation temperature.
I am open to suggestions..