The source code for jshydra can be found at my Mozilla user hg repo. Presently, it requires some hackery and file modifications to merely build the system. I use SpiderMonkey internal APIs (the parsing APIs, to be exact), so that's where most of the hackery comes into play.
For the time being, I'm probably going to put aside doing more work on jshydra, as I have more pressing work on my plate at this time. If you have any questions, feel free to contact me via IRC (handle: jcranmer (I should be in #mmgc)) or via my email address as listed in bugzilla.