Not an expert, but will give you my two cents.

It has totoru in it. Big increase in final price.

It has almost all the main characters in a line. 
Big increase in final price.

The characters are small bodies and the faces 
are not very big. Not as big a negative in the 
states, but a bigger negative in Japan. Drop in 
final price especially if being sold in Japan.

It is from one of the most memorable scenes in the 
film. Big plus.

In all, I would probably guess that in Japan it 
should go for around 1,200-2,500 dollars. However, 
if it was on yahoo japan and several people really 
decide they have to have it, who knows what price 
it could go for.

Marcus