Hi Caryn! It'll cost 1,050,000 yen (without tax, with a non-japanese passport) for a 35cm Togo Birkin. It costs 990,000 yen for a 30cm Togo Birkin. Not too sure of the exchange rate to USD and it will definitely be more expensive in Japan but the chance of strolling into a boutique and coming out with a Birkin is worth the premium to me.
The odd thing is all stores were unwilling to check with other stores (it's some kind of policy because of the high volume of requests by tourists to do so) for their stock. It's best if you call personally to check in case you don't find something in the first store you go. Another tip - there's this super luxe H boutique located in the Ritz Carlton (at Tokyo Midtown) but you would need to make an appointment to enter the store. It's an appointment-only place. There were tons of exotics there though (even bi and tri coloured ones). =) Good Luck!!!!