You can get a AVIC in Japan with Japan's maps on it but with the Z1's there is no maps to load. It is all on the HDD. I looked into it and they also have some in Europe with maps of Europe. I checked out the Pioneer Asia website and they don't even sell navigation there. You will find that a lot of the Japanese based items do not get made for its neighbors. Japan isn't liked too much by them and vise versa. You might find that the Korean based electronics manufacturers may have GPS offerings. Look at LG, Samsung etc....
I suggest that you look into getting a portable solution like a PDA. They are the only ones that I could find that had GPS maps at all.