Actually it's a feature of Rails that the same module doesn't get loaded multiple times.
We started to use the normal ruby module inclution hooks and it worked fine!
module CustomConcern def self.included(base) custom_class_lookup_paths = ["#{HOSTNAME.camelize}::Models::#{base.name}PrependConcern","#{HOSTNAME.camelize}::Controllers::#{base.name}PrependConcern" ].map{|class_string| class_string.safe_constantize }.compact custom_class_lookup_paths.each do |class_string| base.send :include, class_string end end