http://www.anandtech.com/show/5033/amd-releases-catalyst-1110-driver-package
"The full release notes don't mention the Battlefield 3-related enhancements highlighted in the 11.10 beta release, but five-display Eyefinity configurations (of a maximum resolution of up to 16000 x 16000 pixels) are now supported, and a new "bezel compensation" feature can adjust for displays with different pixel densities."
Does that mean BC can be used with mixed monitors?
Yes, but your satisfaction is not guaranteed. ;-)