what about this design?
first you install 4 push pins, sorta like the ones on the blue orb, but bigger into the 4 socket motherboard holes. then a metal plate is placed on the 4 push pins, but the push pins will have springs on them. then the metal plate is bolted on to the push pins, and as the bolts are tightened, they will make the metal plate push down against the springs and will provide clampin pressure on the waterblock.
a little confusing, but hope you get the general idea.