Sounds like a great idea, BUT:
Are you saying this dog is a devil in a funny way, or serious PIA way? How does your wife feel about this type of dog?
If an owner is deployed, she can't say she's going to do it, and then halfway through decide it's too much, and quit.
Some dogs are just going to be PIA's. I've lived and bred such a breed for 25 years and was VERY selective in choosing homes for the pups.
Owners who want to hire her are not going to say their dog is a devil, owners usually don't think so, so she needs to be aware of things that indicate a potential client's dog is a PIA.