"But I feel that in order to prepare for the shock and violence of a high level fight, you have to train at least in some way the concepts of NHB.
That means cross-training, sparring with resistent opponents, and doing realistic drills, heavy bag, ground and pound dummies, etc."

When you say cross-training, do you mean in several different styles, or preparing for all different ranges of combat?

If you do a traditional style (just for the hell of it, let's say....bagua) there's nothing preventing you from sparring with a live opponent, or doing live drills, or any of that. In fact, if you want to develop real fighting ability, it's a must. I always get a little irritated when people refer to live sparring as "modern" training. No, it's been around for a while. I'd call it "smart" training.