When I went to Celine at Selfridge's in September, they had Celine box bags on display, but didn't have any left to sell. They were expecting to get more the next week. I'm not sure they normally sell display pieces, because they have been scuffed up. I'm not sure about the luggage in particular though.
Have you checked the store locator on their website?
I did and I made an appointment with one of the Paris stores. Hopefully I'll come back with something!