Rails 4 + append_view_path

The Devise gem has a way of adding views lookup path by overriding the _prefixes method:

class DeviseController < Devise.parent_controller.constantize
  include Devise::Controllers::ScopedViews

  # Override prefixes to consider the scoped view.
  # Notice we need to check for the request due to a bug in
  # Action Controller tests that forces _prefixes to be
  # loaded before even having a request object.
  #
  # This method should be public as it is is in ActionPack
  # itself. Changing its visibility may break other gems.
  def _prefixes #:nodoc:
    @_prefixes ||= if self.class.scoped_views? && request && devise_mapping
      ["#{devise_mapping.scoped_path}/#{controller_name}"] + super
    else
      super
    end
  end

end

Can this be applied to your use case?

See source:
https://github.com/plataformatec/devise/blob/master/app/controllers/devise_controller.rb