I might be able to get you a picture of the Sapphire 290X 8GB pcb if needed, just shout.
If you could, extremely difficult to find as it just throws up 4GB versions in google
So the Sapphire one may work with reference blower?
http://www.overclockers.co.uk/showproduct.php?prodid=GX-359-SP&groupid=701&catid=56&subcat=1752
Yes, though I can't find any PCB pics of this either, the fact its the reference 290x blower cooler is enough to tell me it is the reference 290X PCB, could always quiz gibbo as he had those made just for OcUK
General rule of thumb for GPU water cooling: Buy the cheapest reference cooled card you can, as 99% of the time it guarantees block compatibility.