Sorry for your troubles. I know you must be very disappointed.
Why on earth would they put caps back there?
They have to expect enthusiasts to use aftermarket HSF, many of which use backplates in that precise area.
Many stock CD2 go up to 3.2GHz with no voltage increase. I am not sure the stock fan can handle it though. That will depend on the air flow in your case and your temps under load, I'd probably try 3.0-3.2GHz.
If you want to be "safe" and your chip doesn't need extra volts to do X6800 speed, I'd just sit on that until you figure what aftermarket cooling you are going to go with.
If you want to stay with air I know the Scythe Infinity and Mine do not use or need a backplate. They secure much like the stock HSF.
Note: I am not sure either of the above HSF would work on the Evga 680i. I only know they do not require backplates. I am asking around to see if I can get an answer.
EDIT: This fellow got the Infinity to mount and he said he did a mod on it to ensure it would clear the caps. Look at the pics in post 7 and 8. You could probably PM him if needed for specifics:
Here are the caps I'd be concerned about from said post: