Breach of bond? maybe...
But - even if it is not, the fact that you're on a bond is reason for the magistrate to throw the book at you for the driving unregistered because you're demonstrating that you think you're above the law. Register your car, or walk... BTW with cameras mounted on police cars these days your chances of getting away with unregistered driving are not great. As far as stupid crimes to commit, driving unregistered is well and truly high up on the list..
Look I'm no saint - 20 yrs ago, I drove around unregistred for a few weeks. I was young, and poor and didn't have the $$$. But the fact is these days with the technology the cops have, you're gonna get caught. NOT IF, or MAYBE - YOU WILL.