Sorry, but I have no recommendations about books for you.
I actually wonder if a book will be particularly helpful to you. You already seem to understand the principles of using your current camera and those principles will be the same when using your D7000. I purchased a book for learning how to use my D80 because it was my first dSLR. However, I didn't purchase a book when I upgraded to the D7000 and I don't miss that I didn't.
As an example, reading a book probably won't help you benefit from the fact that the high-ISO capability of the D7000 is so much greater than your D40X. If your D40X doesn't have Live View, perhaps a book will help with that. However, you could download the PDF of the D7000 manual now, which (surprisingly) explains Live View quite well. There are some other new capabilities such as the Virtual Horizon that your D40X doesn't have, but they seem to be very intuitive.
You might consider first reviewing the manual's explanations of all the menu items if you haven't already done that. Doing so will at least inform you of the specific capabilities that the D7000 has that your D40X doesn't have. Then if you still think it might be worth the time required to study a book, that would then be a good idea.