Batman and Star Wars would be a pretty sweet crossover, with Batman battling the Imperial Army forces while trying to contain his own dark side.
But this fan art mashup by Dean Fraser contains concepts I find a bit strange, like the fact that the Joker is the Emperor and is therefore Batman's superior, or Nightwing being directly opposed to Batman as Luke Skywalker, but the character designs are spot on and very well done so I guess strange concepts be damned. Funniest character mashup in this series- Penguin the Hutt!
Link --via BuzzFeed
There's more relevance there than him being the Emperor...