In Thailand and some other countries it's already 2555 year since they use Buddhist Calendar and there is offset of 543 to gregorian one. Not a problem in #ruby and #i18n As i18n support not only YAML files but ruby hashes also it can be easily localized.

cat config/locales/th.rb

{
  th: {
    date: {
      formats: {
        default: lambda { |date, _| "%d.%m.#{date.year + 543}" }
      }
    }
  }
}

and then just use I18n.l method:

ruby-1.9.3-p194 :032 > I18n.l(Date.current)
 => "30.10.2555"