[Simplex123]

like kardboard had said earlier "Sometimes the same phone is offered on other carriers outside of Japan,"
MOST sharp/toshiba/panasonics are NOT released outside of japan as another version. because a lot of the older japanese phones weren't even equipped with GSM. they only had wcdma. it was not until the docomo 905 series that their phones have gsm on it.

the nokia 705nk was not a good example.. just look at all the other phones on the site.
you dont see many of them in our market do you?
you can probably buy, say a.. sh906 in a electronic store in japan, but it will not be another variant of it. it will be the exact same one docomo is selling.

IMO. the japanese do not like selling their products out of their country, instead, they like to keep the best for their own country (might sound kind of stereotypical, but i believe it is quite true at times. i guess they are slowly changing that thought though. just my own opinion though.) because i really cant find a reason why some japanese phones would just lock themselves until they detect a japanese network.

and for your question..
"wouldn't it be easier to get it straight from Toshiba instead (eg. Toshiba 904T, and assuming that you don't need any form of hack for a phone that is straight from the manufacturing company)?"
even if you could get one from toshiba, it will still be the same one, for the exact reason i have stated above. you will still need a hack for the phone to use it here, because japanese phones are not locked to their carriers, but for us to use it, we have to hack the phone to thinking that we are using a softbank/docomo simcard.

sorry if some of the points aren't that clear, i didn't get much sleep last night and had summerschool in the morning.. = =
it'd be great if someone can clear up some points that i have missed or mistaken. lol