Don't go SLI or CFX and you won't need the watercooling either..........also micro-stuttering is to consider when going that route.
if you wanna run 3x27" of UHD.....thats a HUGE number of pixels to push!!! and CFX and SLI setup of 2GB+2GB cards are Not 4GB but ONLY 2GB EFFECTIVELY...
so, I would recommend going with a single card solution.
GTX Titan is coming out in a week on 2/18.....should be available to ORDER in about 10 days.........6 GB, 384-bit ......that's what you need to run 3x UHD displays
so hold on for 10 days, and get a Titan. because CFX/SLI has microstuttering + heat +space + efficiency problems....
and NO single card currently available is gonna cut it for ur needs.
its gonna all change in a week.