Hi,
The custom models don't seem to be quite as sort after as the burst models. In the UK my guess would be around ?550 max. but at the end of the day it's worth what ever someone will pay for it. I've seen fairly high end sought after models go for all sorts of prices. Prices vary depending on where you are and import duty etc - you'd get one quite a bit cheaper from Japan but the customs charges and duty etc make quite a difference by the time you get it home. What coulour is it? Any pic's?
Dave