Not sure how evil you want to get with this, but several years back I wrote a simple, but nasty test that picked a cpu at random, and set the state to the opposite of whatever it happened to be at the time.  It was completely random, I didn't have anything builtin for record/playback, or doing it in the same sequence for reproducibilty, but it didn't really need it.  When it broke things, it usually broke them within just a few minutes. 

Thanks,

Paul Larson