Hi, thanks everyone for the replies.
I definitely don't plan on buying the entire rear seat in Japan; it would be a crazy expense. I was curious to know if they produced cars with an armrest in the rear seat in Europe, so I could do a search, perhaps even looking at used ones.
Is the Civic's rear seat the same as the Jazz's?
I've seen that armrest-style bag that fits in the rear seat, but I don't like it; it's not what I'm looking for. I'd like something more refined, just like the fold-down armrest found on Japanese models.