It's a fantastic tribute. So well done. This will be worth a great deal in the future, and with The Killing Joke re-released to capitalize on The Dark Knight coming to theaters in a few months, this cover becomes all the more topical. I'm going to have to eBay hunt for this one, since I just bought The Killing Joke on hardcover...
It's lovely! First time I saw it, I about had a coronary from joy! Being an old-skool Batman freak (I was FRUIT for The Joker back in the day!), this cover knocked me down! Very nice indeed!