Hey Mercury,
The Swiftech MCW50-T is almost exactly what you have drawn. It uses a water-cooled 80 watt Peltier for graphics processors. The hot side of the Pelt is in direct contact with the cooling water. The Swiftech water jacket is square instead of pyramid shaped. It works quite well...
I just finished a review of the MCW50-T which should be posted this weekend over at
SystemCooling.com