I just bought my second GTX 560 TI for SLI today and also picked up a new 1000w OCZ to support it. I tried a quick bench mark test on Bad Company 2 with every maxed out 1920x1089 eect ect it ran perfectly at 60fps solid with no dips, but my fans start ramping up pretty high and my checked my temps and they were around 80-100 degrees!
When installing the cards they were very close to eachother and my case isnt big enough for me to put my second car into the last PCI-E slot because of my PSU being there (Cooler master case) So am I just blowing smoke about all this or is this a cause for concern?
Id consider getting about 2 more fans on the side and infront of the cards but as it is i have 2 fans ontop, one one the side and one at the front of the case. Or maybe just a whole new case, not alot of room for SLI's to breath in my cooler master, unless there is a different problem.
A couple 120s (or whatever will fit)on your side panel is what you need to keep temps in control. You could try Vsync + triple buffer on BFBC2 since 2x 560 ti doesn't need to be pushing at 100% all the time, even with everything up. Or if you don't like Vsync, you could try some other form of frame limiting. I've never done it in BFBC2, but I'm guessing it's possible through a config file.
EDIT: I have two GTX 460's in SLI with no space between them and a cheap 120mm fan positioned right over the top card dropped its max temp from 89C to 79C.