Funny you should mention Highly Sensitive Child. I was very active on some threads about this a year or so ago. Then, some posters got all ticked off about the "labeling" issue, the thread went severely wonky and I have cut way back on discussing it on MN. However, yes there is an excellent book on the Highly Sensitive Child by Elaine Aron. I think you would find it invaluable reading. Did I already mention the book Raising your Spirited Child? It is an excellent companion to the other one.
As far as saving it up for home, behavior-wise, that's our situation as well. He's the perfect child everywhere else, apparently. The OT explained it to me on Friday thusly: "Imagine that you are having a really stressful day at work. You hold it together b/c you have to, then you come home and take it out on your husband."
err, have to say I really got it at that point