The Z750a is nearly the perfect phone. sleek, tri-band umts and quadband gsm, and display japanese. only problem is you can't input japanese for some bs reason. i can buy it direct and put it on AT&T and roam in Japan or rent a SIM card.
the M702iS is basically a Japanese version of the razr V3xx. but it's locked. but the techie in me is thinking dissecting an unbranded, unlocked V3xx, swapping the guts with the M702iS, and installing the japanese language pack on it.
http://www.motorazr.jp/
http://www.sonyericsson.com/spg.jsp?cc=us&lc=en&ver=4000&template=pip1&zone=pp&pid=10875