Take a look at this thread from overclockersuk
Backplate for the Gigabyte WF3 GTX 780 & 770 anyone ? - Overclockers UK Forums
I went this route with my Gigabyte GTX770 ,but be warned it's not a 100% fit on the 770.
The pcb of the 770 is not the same as that of the 780 ,but with a little modding of the EK backplate it can look okay ,but the card and the backplate will have a small gap at the end where there are no holes.
Since I got my Gigabyte GTX780 the EK backplate fits flush with the card as all the mounting holes line up and it looks real smexy now in my case