@strawCake - This does sound like kind of a cool job. However, I think I would hate the part where you have to deal with the family and explain what's going on to them.
I imagine that most people who have loved ones with traumatic brain injuries aren't exactly at their best. They're probably upset and stressed out! I think it would be hard to relate all the information to them. You would have to explain it to them in a way they understood (obviously the average person doesn't have the same knowledge of the brain as a neuropsychologist) and be sensitive at the same time.
I think it would be especially rough to be a pediatric neuropsychologist and have to give bad news to parents all the time.