Does your buddy need to travel back to consult with customers in the US (assuming that is where he is from)? Was he an established consultant before the move?
He does have to travel to meet with clients, but from what I've gathered, it is not particularly frequent. He had a pretty solid resume as an engineer and is definitely one of the most creative, smart people I know, but I don't think that he had much of a list of prior clients. As I recall, our school kind of set him up with his 2 main clients. Its quite a bold move on his part and inspiring to me. It's only one data point, but its certainly an example of how its possible to carve out a niche.