When I first designed the P-ROC, I had a JD and used it as a dev platform for custom custom software. The result was a new, custom ruleset for JD, deeper than the original rules and functionality complete, including a 4-stage wizard mode (alternately enabled via the supergame button).
After getting some volunteer help with voice calls, music, and DMD artwork and animations, the game turned out pretty well, though it could admittedly stand some more work on dots.
We demo'd this custom JD code at Chicago Expo in 2010, letting people play it throughout the weekend.
Unfortunately, I sold the JD and moved on to bigger and better things (Multimorphic and the P3!!!), but the code is free and open-source, and anybody can install a P-ROC and play the code on their machines.
Wiki page: http://www.pinballcontrollers.com/wiki/JD_rules
Source code: https://github.com/preble/JD-pyprocgame
Discussion forums: http://www.pinballcontrollers.com/forum/index.php?board=12.0
How to buy a P-ROC: http://www.pinballcontrollers.com
If anybody wants to revive and take ownership of this project, PM me. Since the code is all written in python, you don't need to be a low level software expert.