As Alexandru says above, there are reviews of the 350D/Kiss N camera here
where it appears to confirm that the camera is of universal build, with the menu screen being able to be changed to one of the 15 languages (including Japanese) supported. The physical differences seem to be cosmetic.
On the 300D/Kiss, the Japanese version supported some features as standard not included elsewhere, for example IR
control. Otherwise is was the same camera as shipped throughout the world. It may be the same is true of Kiss N, where you may find extra features that are locked out elsewhere. I would also guess that the camera will be supplied with Japanese and English manuals (my Canadian 300D had French and English manuals).