So I have an almost 3 year old bull dog (hard to believe she'll be 3 in a couple of weeks!) - I had a similar mindset when she was a pup. "She's SO smart!" "She needs a job!" So naturally, I started researching which jobs would suit her best based on her breed and personality. IPO and other bite work is huge in my breed. When I started researching things like IPO, etc. I discovered exactly what everyone is saying above. A trained protection dog is more often a liability rather than an asset. And training a dog in protection "for fun" isn't really giving the dog a job when those skills are never actually put to use. For dogs like ours, where "guarding" and "protection" really come naturally, training in obedience is the best way (IMO) to mentally and physically stimulate the dog, while also not squashing their genetic tendencies.
I'm very happy that the people here on this forum are so knowledgeable and were honest enough to tell me about the downsides of training in any sort of formal protection work before I went off half-cocked into that world. We have moved through advanced obedience, and she's a fantastic dog with a natural protectiveness that I don't have to train or manage, really. She understands boundaries, and pity the fool who tries to open the car door while she's in there - or the strange dog who comes onto our property. Just yesterday a large brown lab showed up at our house (I live on 20 acres in a rural setting) and she just stood her ground and barked him away. I didn't teach her that, she just automatically knew what to do. When I told her to "leave it" and come back to me, she ceased her barking and did just that. So. As I see it, obedience training really serves to support and enhance their natural instincts. I have come to believe that the only reason anyone should train their dog in IPO or other bite sports is if that is going to be the dog's *PRIMARY* function, which is going to require full time dedication above and beyond a 40 hour per week job. These dogs are not pets in the standard sense of the word. If I were you, I'd encourage your husband to focus on going through obedience levels, forgetting the protection training, and perhaps pursuing the CGC, and/or other things like agility. Since you are active in a training facility, I'm sure you're exposed to all the different paths to keeping your super smart dog happy and stimulated.