Monkey patch Mail to word wrap every body before delivery

mail-message-word-wrap.rb

module Mail
  class Message
    include ActionView::Helpers::TextHelper

    def deliver_with_word_wrap
      self.body = word_wrap(self.body, :line_width => 70)
      deliver_without_word_wrap
    end

    alias_method_chain :deliver, :word_wrap
  end
end