module Bar
  def hello
    "original"
  end
end

module Merb
  METHS = {}

  Bar.instance_methods.each do |meth|
    class_variable_set("@@__meth_#{meth}", Bar.instance_method(meth))

    class_eval <<-RUBY
      def #{meth}(*args)
        @@__meth_#{meth}.bind(self).call(*args)
      end
    RUBY
  end
end

module Baz
  def hello
    "new"
  end
end

class Foo
  include Bar
  include Baz

  def merb!
    extend Merb
  end
end

f = Foo.new

p f.merb!.hello