There used to be a Java Emulator at one point, several years ago, which means it probably doesn't include CAN instructions. But at last look all I could find was a single dead link to where it used to be.
I take it you're looking for something that you can trial your software on right? I don't know of anything, but good luck searching.
However, if you get frustrated and choose to write one, there's obviously a market opportunity at the moment for that sort of thing....
Although the post is fairly old. I'd like notice folks which will be interested that we've written a ELM Emulator. Actually it's little more than a ELM emulator because that's emulate an ELM connected to an ECU..
We're using it to test our software (you can see it at the following link http://sites.google.com/site/outilsobdfacileen/home)