Jurassic Park 4 is actually currently in the works, with Rise of the Planet of the Apes writers Rick Jaffa and Amanda Silver writing the script, and a release date of summer 2014 in mind. But when you're making a sequel to a movie that enormous, of course there have been earlier versions of the story, and a glimpse at the Jurassic Park 4 that might have been has just emerged, and perfectly timed to Halloween, as it turns out.
The rejected concept art images come from a 2005 script written by William Monahan (Oscar-winner for The Departed) and John Sayles (director of indies like Lone Star and Matewan, but also write of more Hollywood films like The Spiderwick Chronicles and Battle Beyond the Stars). Around that time producer Frank Marshall was out there suggesting that Jurassic Park 3 director Joe Johnston would be returning and they were firming up the script, but of course, the movie in question never got made. And when you look at the human-dinosaur hybrids that would have been at the center of it, you might know why. Take a look at the handful of images below.
There's much more where that came from over at Neogaf, where user Demoncarnotaur posted them and explained the connection to Monahan and Sayles's script. Apparently the action would have happened after a secret genetics lab was cross-breeding human and dinosaur DNA, because even after the original Jurassic Park nobody realized that tinkering with dino DNA was a terrible idea. You can read a review of the original script, or at least a version of it, over at Aint It Cool News, though that review makes no mention of dinosaur-human hybrids, so I'm not really sure where these came into play.
None of this ought to have any bearing on the version of Jurassic Park 4 currently in development, though given how Jaffa and Silver dealt with genetic modification in Rise of the Planet of the Apes, there might be some similarly crazy scientific developments anyway. Just enjoy these images at a glimpse into a parallel universe version of Hollywood, where human-dino hybrids would have been giving you nightmares for yearsnow.
