I found this “Firestorm Games” site that does free international shipping on orders over £30.
http://www.firestormgames.co.uk/12535
It’s ten pounds more than Total Wargamer, but still not too bad.
(the prices on their other stuff’s not so great, though).
[edit: nope, they can't ship GW products outside of Europe, either]

There were a couple ebay stores that have it for fairly cheap, but neither of them look like they can ship to Japan, either.

Same problem as Total Wargamer: they can’t ship outside of Europe.

(which is really unfortunate, as their prices were really good, and their shipping was the most reasonable I’ve seen yet).

you’d be lucky to find anywhere except GW that will ship outside Europe, GW put up a policy to stop independent stores from shipping out there. remember all the trouble Wayland went through not long ago?

Alternatively, I can wait till someone I know heads back to America and I can ask them to pick one up for me.
The problem there would be that probably wouldn’t be until summer. That’s a long time to have to wait, and there’s nothing saying that they’ll even still be available by then (some of these battleforces sell out pretty quickly).