if k3b is emerged on a system with lcms installed but the lcms use flag off, then it depends on lcms anyway. If you then uninstall lcms, k3b stops working. Upgrading k3b to 1.0 without lcms installed fixes the problem. So somewhere in the k3b dep tree there is an automagic dependancy, but I've no idea where.
*** This bug has been marked as a duplicate of bug 174826 ***