No, unfortunately, it's not possible yet. There is something called the XDG Base Directory Specification which makes certain types of directories configurable, including where apps store their data, where their configs are, etc. It says that configuration files should be placed in a directory specified by the variable $XDG_CONFIG_DIRS, which is $HOME/.config by default, but many applications doesn't use that yet. This is very annoying for many reasons. When they do, then it will be possible by simple changing that variable to something else, like $XDG_CONFIG_DIRS=/somewhereelse/.config. For now, it is not possible for things like compiz, but it is possible for many other things.