Well here is my reasoning:

The N900 was made in Korea and the N8 is made in Finland.

My geographical skills tell me that Korea is further away than Finland (I am from the UK), so therefore the transport costs would make the N900 more expensive.

But the only problem is that this theory would only be valid for European, African and possibly American market.

It didn't make any difference to me as both my N8 and N900 are on contract...