I just came across this film, which is called project G from 2008. Running at just 48 minutes long, this film tells the story of a man who turns into a giant monster and goes on a rampage across Japan. As the defense forces fail to stop it, a giant robot is sent to stop it, in very much Jaeger vs. Kaiju fashion.
Written and Directed by Kiyotaka Taguchi, who worked on the Godzilla films between GMK and Final Wars in the art department. And he has also done a lot of digital VFX work. Whew, what a portfolio. He made this film over the past couple years, whenever he had the time to. Very cool, indeed.
Check out the trailer below!