In the following pic I'm trying to illustrate how a block that's made to be placed "in a 45 degree" angle related to the video card's edges can be bigger than one that is aligned with the edges. the drawings were made quickly and they're not in scale but they show where the holes on my GF4 MX440 are placed (related to each other and the chip, not the PCB itself because it doesn't really matters..).
The last drawing is my idea for the block (outside part now), it has to be conical to cast nicely and that may be an advantage because the hose fittings being inclined will probably put less strain on the board (because it doesn't has to hold the weight of the hoses, they'll be coming from below).
The "top" (mobile part) of the block is actually the part that goes in contact with the chip, the support will probably be better with the retention part of the block being very close to the board itself, to understand it better look at the outside of my CPU blocks in the other thread and imagine them being placed on the CPU (in out case the GPU) backwards.
http://www.advancedcoolingsolutions.net/bruno/GPU3.jpg
I think this post has gotten pretty confusing, my english is not good enough to explain mechanical details like these, I hope you understood what I meant.
@Holst: I like that, I would have to do some modifications for it to cast nicely but it's something like the basic design I'm looking for.
Thanks
Bruno