One person horse - Great. I can handle that in a house cat. Not sure my delicate nature can take that kind of rejection from something larger than me. While it's not ideal, I guess I can hope that "his person" is actually a member of my family. Haven't seen that emerge yet, though.
Trainer/Time/Commitment - I believe we've decided to employ all three. We found a trainer in Des Moines, Iowa that we really like and seems interested in working with Hell Horse. In light of the "one person" mentality you're telling me about, I won't be the person working with him. He's better fitted to one of my daughters - probably the fearless one. So I think we'll get her to put in the time with the trainer and watch for positive growth in both of them (my daughter and the horse - I expect the trainer has grown enough).
Admittedly, he pissed me off pretty good and scared me more than a little, but we can't bring ourselves to give up on him. We made a commitment when we bought him and I don't want to give up on that.
I really appreciate all of your input and encouragement. I'll keep you posted on progress.